Recently, I ran into an annoying glitch – every now and then, all other Zwifters would disappear from the screen and the “Zwifters nearby” panel on the right-hand side of the screen would disappear as well.
This seemed to be happening in almost every Tour de Zwift event which my son or I were riding. It felt like a disaster: you can no longer draft, you lose your speed, and by the time other riders reappear you find yourself dropped and far behind.
Zwift attributes this to a poor Internet connection. Although this makes sense, it did not sound like the whole story. What does “poor Internet connection” mean and how do I fix it? I could browse the Internet on the same computer that runs Zwift while my son was riding and complaining about the issue. Ride Ons were coming through while other riders were gone. If the Internet was gone, nothing should work!
This warranted an investigation. I would like to share this with other Zwifters, since it may help you if you’re encountering similar issues.
Using Zwiftalizer to Spot Network Problems
First of all, I found that uploading my Zwift log file to Zwiftalizer.com is a quick and easy way to test if there were any significant internet dropouts. Zwiftalizer generates a graph for network performance at the very bottom of the report, way below the graphs with ANT+ and Bluetooth signals. If your Internet connection had outages, the network performance graph will show multiple red bars.
The example below is a simulation of a poor Internet connection which I created by disconnecting the network cable for short periods of time and connecting it back. My Zwift log did not record a 2-second disconnect, but was able to detect and save in the log file every disconnect that lasted 4 seconds or longer. Every time the network was interrupted for more than 6 seconds, all other riders would disappear by the end of the 6th second. A 4-second interruption had no visible impact on Zwift.

But what if this log does not show any network errors? What if it shows a perfectly straight horizontal line? Below is the log from a Tour de Zwift ride when I lost all other Zwifters for nearly 10 minutes – and yet, nothing appears to be wrong with my Internet!

The Latency Deadend
I sent a message to Zwift support and asked for guidance. They brought to my attention that they found UDP warning messages in the Zwift log file and recommended that I check my network latency using a generic Internet speed testing web site.
I was still asking myself how latency could be relevant to this issue (after all, Zwift may run for as long 6 seconds without any incoming data until riders disappear- this would be a huge latency!) but I decided to check anyway. And I had an even better idea: my firewall log shows IP addresses of every server which Zwift talks to. Why don’t I ping one of those servers (preferably a server which sends UDP data)?
I was lucky to find that one of several cloud computing servers to which Zwift talks during a session was accepting pings (the others did not). I found no issues with latency: it was around 23 ms for a round trip to a Zwift server (this is a good, low number). So, the latency hypothesis was a dead end. Yet, I found something else: 2.1% of pings were lost along the way and never came back – which was a bit alarming! (In retrospect, it turned out that packets were lost within my home network and I could get the same result by pinging any random web site).
An Important Discovery
There was one more unexpected and important finding, this time from the log of the firewall running on my PC: my own firewall was rejecting part of data packets coming from Zwift servers! The fraction of rejected packets varied. Most of the time it was low, a fraction of a percent, but in the moments before losing other Zwifters it was particularly high: I estimated that as much as 4.6% of Zwift’s data packets were rejected!
With this information in hand, a picture of the root cause of my problem started emerging. My Internet connection was stable if measured on the scale of seconds and minutes, but a fraction of data packets were getting lost. It seems Zwift is sufficiently robust to continue operating without issues as long as the fraction of lost packets remains below a certain threshold, perhaps a couple of percent. But once a cumulative losses becomes high enough, an issue starts!
It became clear that I needed to find a way how to fix one or both of two sources of data loss: the issue caused by my wireless network and the issue caused by my firewall.
Fixing My Network Losses
I have a fairly complex wireless system at my home. In my home office, I use a separate router in the bridge mode to be able to connect my work phone which requires ethernet. The same bridge feeds Internet via a short ethernet cable to the computer which runs Zwift.
I ran a sequence of tests and found that data loss only happens when I use that bridge. If I connect my PC directly to the cable modem using a long ethernet cable (instead of wi-fi), my latency drops by about 2-3 ms, while packet losses disappear. If I connect the PC directly to wi-fi to circumvent the bridge router, packet loss also disappears. Hence, the problem with my home wi-fi turned out to be easy to solve. I did not even need to hardwire my PC to the cable modem! My best guess why this happened is because my bridge router sits under the desk in the office, in the area with a relatively poor wi-fi signal (around -73 dB, per WiFi Analyzer).
The second source of losses, related to firewall, is a little harder to understand…
Fixing Firewall Losses
TCP vs UDP: a Zwift Primer
Before I explain what I changed to fix that second issue, let me take a step back and discuss a couple of technical questions, so that you are on the same page with me. First of all, how is it possible that a fraction of data packets gets lost, but the log file (graphed by Zwiftalizer) shows a stable internet connection? This is where it becomes technical.
Zwift uses two Internet connection protocols. They do not disclose what data they send and how they send them, but it appears that the TCP protocol, the more reliable of the two, is likely used for things like connections to databases, retrieving routes, uploading rides and pictures, text messaging, and Ride-Ons. The second protocol used by Zwift is UDP, which Zwift appears to use to send your current position and power to the servers and to get information about nearby riders back from the server. These data packets are sent back and forth continuously, so Zwift can show the true positions of other Zwifters at every moment.
Zwiftalizer analyzes and graphs only the status of TCP connections. Since TCP requires two-way negotiations with confirmation of data delivery and includes the option of resending lost data packets, Zwift very quicky learns about connectivity issues and creates an error message in the log.
UDP, on the other hand, is one-way communication without confirmation of data receipt. Therefore, it may take longer for Zwift to notice an issue. When it gets data at a slower pace or does not get at all for a short time, it cannot determine if the network is not working, a Zwift server is not working, or if data packets are just delayed because a server is overloaded and cannot catch up with the demand.
A comparison of my firewall log with Zwift’s log suggests that each time Zwift suspects the UDP connection is poor, it tries connecting to a backup server. If that does not help to restore full connectivity, it creates a somewhat obscure warning message in the log file which looks like this:

This warning message is the indication of a potentially significant UDP data flow interruption. If one or two data packets are lost every now and then, Zwift does not seem to care.
These messages are a valuable tool for troubleshooting. Just open your log file and any text editor to search for “UDP”.
Stateful Firewalls: the Basics
Back to the firewall. How is it possible that a firewall would reject some packets but not the others, if they come from the same server? I have a hypothesis for that. Many, if not all consumer and small business-grade firewalls by default allow only application traffic. They maintain so-called session tables for TCP and UDP to quickly decide if they should pass or block each incoming data packet, without scrutinizing the contents of the data packets for signs of malware.
When the local Zwift program sends a UDP data packet to an external server, the server’s IP address and port are added to the list. If the firewall gets an incoming UDP packet, it searches the session table for a matching IP address and port. If it finds a matching entry, it decides that it is a legitimate data packet and lets it through.
If there was no traffic for a certain time (which can be very short, perhaps just a few seconds or less – the higher the firewall security level, the shorter the time), the entry is deleted from the state table. This is a safety measure, so that no other program could hijack the traffic.
After that, the firewall will start rejecting further incoming UDP packets until a new UDP entry is created in the state table. This matches what I see in the firewall log – UDP packets from remote port 3022 are rejected as “IP traffic”, which means the firewall can no longer associate them with a specific application on the computer. This is a way to say that there is no matching entry in the state table.
Setting Up a Firewall for Zwift UDP Traffic
Zwift knows about the potential impact of issues with UDP traffic and provides the following guidance to users:

Most users ignore these recommendations: “I installed Zwift, it works, so everything is good with the firewall, right?”
As I learned the hard way, apparently not! In my case, my firewall did not let ALL traffic through. It let MOST of the traffic through, with some exceptions. The good news is, it is easy to fix. Instead of relying on generic application-related rules to recognize Zwift-related traffic, one can create a special firewall rule to let it all through.
A special note is due here: Zwift could have done a better job explaining what needs to be done.
For one thing, they only made a reference to the router firewall, but did not mention a firewall that runs on the computer. A firewall on the router may block Zwift completely, but it is very unlikely that it would create intermittent issues. Router firewalls, to the best of my knowledge, do not use application traffic rules. If Zwift works most of the time, your router firewall is “out of the equation” – but the firewall on your computer is not!
Secondly, the Zwift team was not sufficiently precise with what port to open. They left one word out. Internet traffic runs between a remote port on the server and a local port on the computer. They usually have different numbers. Zwift meant to say that your firewall should allow all incoming UDP traffic from remote port 3022. Local port can be about anything: the Zwift application changes it every time it resets the UDP connection, and it is never 3022.
Each firewall has its own interface, and the sequence of steps required to create a new rule varies from one to the next. Microsoft Windows Defender is a very common firewall because it comes standard with Windows. Defender makes it fairly difficult to configure the rule required for Zwift, but here is how it is done:
- Open Windows Defender Firewall
- Click on “Advanced Settings”
- Click on “Inbound Rules”
- Click on “New Rule”
- Pick the second radio button on the list, “Port”, and click “Next >”
- Pick radio buttons “UDP” and “All Local Ports” and click on “Next >”
- Pick radio button “Allow the connection” and click on “Next >”
- Leave “Domain”, “Private” and “Public” boxes checked and click on “Next >”
- Type in a description of your new rule into the “Name” field. For example, you could type “Zwift – allow inbound UDP traffic from remote port 3022”. Click “Finish”.
Now, your newly created rule will appear in the list of Inbound Rules. But we are not done yet! We still need to add the external port to the rule:
- Right-click on this new rule which you just created.
- Chose Properties from the context menu. This will open a tabbed window.
- Find the tab “Protocols and Ports”. Everything in this tab looks like it is greyed out, but in fact you can edit it.
- Change Remote Port to “Specific Ports” and type in “3022” on the line below. Then click OK.
The picture below shows what you should see on this last step. If you use a firewall from a different vendor, you should see something similar, although steps to it may be different.

Wrapping It Up
I run Zwift on a computer with a third-party firewall. I cannot speak to every existing firewall. I cannot tell if all of them, or many of them, are likely to create this issue. The expiration time of UDP state table entry may vary in a wide range. The firewall log is an easy way to find out if any rejections of traffic from external port 3022 have happened.
My experience so far has been that implementation of this rule alone, even without a change to my wi-fi configuration, seems to have fixed the issue. Before the change, we saw riders drop-outs in almost every TdZ race. After the rule was put in place, four races, several rides, and no issues!
So here we are: one persistent and intermittent issue, a week of investigations, two root causes, fixes found for both of them, and everything is now running smoothly. Back to racing!
P.S. A year ago, Eric published an article on a similar topic: how to ride all alone in Zwift. He intentionally blocked UDP connections by blocking outgoing traffic to remote port 3022. This stopped local Zwift from establishing UDP connection with the servers and thereby stopped both sharing of his information with other riders and other riders’ information with him. In my case, I intentionally unblocked incoming traffic coming from remote port 3022.
There is no harm to also explicitly allow outgoing traffic that is headed to remote UDP port 3022, but I did not see any firewall issues with outgoing traffic and did not see a need in yet another rule.
P.P.S. The tools which I used for troubleshooting:
- Zwift log files
- Zwiftalizer.com
- PingPlotter 5 (This is a commercial software. It automatically sends pings every few seconds, plots a graph of latency. and marks lost pings. Fully functional trial version is available)
- Firewall log files
- “WiFi Analyzer” program on my Android phone to check signal levels in my home wi-fi network. Similar programs available for iOS as well.
Questions or Comments?
Share below!
Thank you for this article, Andrei, very helpful!
Thanks for sharing your journey – it was an interesting read. I have added the firewall rule as a precaution now.
Always good to cancel out a possible problem 🙂
Ride on Andrei!
a little too complex for me! I run Zwift from Apple TV (it’s sole use as in a separate building) and half the TdZ races I was riding solo for the first 10-20 minutes. Although I was pushing out 3.5 w/kg (not much I know comparing to a lot of people but goodness it hurt) I ended up dead last in 2 events until suddenly other riders reappeared. I was still last and spent the next 40 minutes fighting to get into the top 1/3. – proved an excellent workout but would have been nicer with others around. I check… Read more »
Kevin, one of my findings was that wireless connection may start losing data packets if wi-fi signal gets weak. This has no visible impact on the internet speed and no impact on how a computer connected to this wi-fi works, except occasional garbled sound during videoconferences or during internet calls. A free app on a phone which can measure wi-fi strength (there are plenty of those for both Android and iOS) turned out very helpful with troubleshooting. If the signal strength is below -70 dB, one can probably expect some dropouts. A program like this is also very handy when… Read more »
I get short episodes of the problem you have described. But I use Apple TV connected to an Internet extender plug in an electrical socket via ether net cable. Any ideas?
Christopher, you are in a difficult situation because you have one black box (Apple TV) plugged into another black box. With a computer, one can analyze network traffic “to death”, but not in your case. The only thought that comes to mind, where does that internet extender plug in the wall connect to? There must be some sort of a DSL modem, cable modem, or some sort of internet gateway on the other end of the cable hidden in the wall. Perhaps something can be investigated and improved on that end.
Great information.
Had the same issue on nearly all TDZ group rides. Opened a ticket on Zwift. Got the same feedback as you: poor internet connection.
After reading your articel I know where to search for the root cause and hopefully I can fix it as well.
Thx a lot!
I’ve had this a couple of times on races and TDZ recently, only lasting about 5 seconds each time. Enough to be a bit freaky and I worked out to push the power so I didn’t lose positions.
I’ll look into this for my firewall. Thank you hugely!
I had this in the fondo ride on sunday for maybe half a minute. Other riders reported it at the same time through the in-game chat. So that was not a problem with the firewall or a poor internet connection.
I can verify the same occurrence during the Fondo on Sunday….
Same thing happened me on Sunday and others all around the world said it happened to them at same time. Was not WiFi
Would be interesting to use Wireshark (network packet analyser) on Zwift network traffic. But agree that a wired ethernet connection seems to be the way to go for absolute stability.
Charlie, I agree! I actually set up Wireshark, but did not get to doing any systemic studies. It gives much of the same information as my firewall log, but it can nicely graph rate at which data packets are coming in. That would be an interesting indication if Zwift servers get overloaded and throttled at times.
Interesting that it’s actually nothing to do with wired or wireless or internet speed! The port forwarding issue was one I had not considered. I have 300mbps speed from fibre and still get many dropouts of other zwifters. Have now set port forwarding so will report on the success if I see it. Thanks
I hope you just misspoke and did not get confused – port forwarding is not the same thing as creating a firewall rule to open a specific port 🙂
The fix was interesting, but the possibility of blocking everyone else is as well!
Great Job Andrei and thanks for sharing!!!
Thank you Mr Istratov. I had this issue a couple of time lately, my Windows defender firewall his not active because I’m using McAfee protection is there something I could change in my McAfee live safe. Thank you for your help.
I do not have a copy of McAfee firewall on my computers, but I can say that all work similarly on the conceptual level and are configured largely the same way. The sequence of steps may be different than for Windows Defender, but all keywords will be the same. It should be easy to find in the internet an article on how to open a remote port for incoming UDP connection in McAffee firewall. I do not know if there are different versions of McAffee security software exist and do not want to suggest links because this may create more… Read more »
very resourceful approach to diminish the problem in our side of things, but still seems to me that not much have been done – or at least noticed on the game’s side. this topic keeps growing without official feedbacks on zwift forums. when the problem happens, the game should be capable of refresh the riders’ list once the connection normalizes, for example. I play many games online, through the same connection, via wifi, and all of them are capable enough to get around dropout issues like those. the list is essential for the race/ride experience, the main feature of the… Read more »
Yes, and many of them have support systems in place to setup and test for these problems. Heck most of them test your hardware at install to make sure you meet the specs too. The chat window in Every major event in Zwift is enough for them to know there is a widespread problem.
great article, but why not just run it wired? All IT pros know, run it wired, wireless is for toys
Same thing can happen wired. It’s not a wired vs wireless issue…
I have wired gaming PC for zwifting and never had issue until January this year, after some Zwift update. Now pretty much daily getting these disappearing issues while everything else works fine (Discord, Spotify…). So annoying really.
I just applied the above trick and will see tomorrow how it goes. Tnx for the article by the way
Thanks for sharing your journey – it was an interesting read. I have added the firewall rule. My wife and I Zwift in the same room and screen freezes have frustrated us many times. UDP messages appear often – so i will give this a try!
Lost me about halfway through…..however I have been experiencing these problems for ages using Apple TV is this the same cause? All complaints to Zwift have been met with replies such as running Zwift concurrently on another device…..
Great piece of work, Andrei!
Sounds like a lot of PR excuses for Zwift servers not handling the large server loads from the big events. If it was truly a user side issue, then why do groups of people during these events all have the issue at the same time?
Don’t go using logic on this now. Multiple years into this and we are just getting over blaming the users for not having $2500 gaming laptops and 1TB internet connections. Say it with me now “you are using a potato, and you have dial up”.
It wasn’t all that long ago that Zwift.exe would end execution and crash to the desktop over the loss of data. That mostly seems to be fixed. Now they need a port test like many online streaming games have had for years and a person that isn’t a computer scientist can fix these problems.
Thanks for a very in depth view on the protocol traffic.
It is a bit strange when Zwift knows about this that they do not build a small debug/test machine, it should be faily simple to biuld based on the already known causes of malfunction
Ride on Andrei!!
And one heck of a lot easier and less resource intensive than the customer support calls that blame everything but the actual problem. I bet they will deploy one eventually.
I got this before the last update over Xmas; but, it was on Apple eg this happened on 2 different Ipads and an iPhone. Clearly none of these window fixes apply to IOS, but thankfully the latest patch seems to have resolved it. It was epically frustrating!!!
Best troubleshooting advice I’ve ever seen for a very frustrating problem I sometimes encounter on Zwift. Thank you.
Hello Andrei
I live that during many episode of the TDZ and with Pace Partner training, I spend 400$ to changed my router and acess point, I ran cables into walls to wired my computer, I still having the issue, Now I will test this and I hope it will resolve the issue, Thanks a lot for your complete description, it’s very helpful.
Nice work in troubleshooting. Is it correct you have configureren now to allowed remotevport 3022 for all remote servers (not online ip adresses from servers zwift uses) ? If this is thr case, in my opinion this could be a security risk, because all the servers on the internet are now allowed to sent traffic to port 3022. Is this correct?
Yes, this is correct. This adds some additional level of risk, although not a big risk. Unfortunately, Zwift speaks to at least 6 Amazon Web Services cloud servers at in any given session and it appears (based on my limited dataset) that the servers themselves or their IPs may change from session to session, or over time. This is the nature of the cloud computing, unfortunately. I would also prefer to be specific down to the IP address if I could.
One friend tried this (adding firewall rule) to his ethernet wired PC yesterday but he still got a disappearing issue on a ride. Any other idea what can be done?
Does it make sense to do a 3022 port forwarding to a fixed internal IP of zwifting PC? Will this help
Uros, not sure if this is even possible. Please consider that we are talking about remote port 3022. This is the port on Zwift server, not a port on your cable modem or on your PC. Your home modem/router can map your local port, which in zwift is always a four digit number, but I doubt it can forward port on a Zwift server… or at least I cannot quite imagine how this would work, even though I do not consider myself an expert. Also, please ask your friend if he/she did not mix up a local port and a… Read more »
In Windows Firewall there’s a rule setting for “Programs and Services”. I don’t have knowledge or experience with using this, but perhaps it could be used to specify Zwift.exe to reduce the risk?
Keep in mind that it is only incoming port 3022 for UDP traffic, not TCP. The vast majority of traffic that is on our home networks is TCP. The risk, therefore, is rather small.
Wonderful! This has been happening to me recently. Cost me several places in my ZRL race last week where I lost others for 30s and lost my group. Thanks again!
Thanks for sharing this Andrei, I have been encountering the very same problem much to my frustration. It happened to turn a “recovery” ride into a big effort because I found myself alone with no possibility of drafting. I have now made created this new firewall rule and will hopefully be able to come back here with good news!
This has been happening to me almost daily since Stage 6. It didn’t happen before except very rarely. Maybe once every 6 months. This leads me to believe something has changed and since it seems to be fairly widespread that seems to make it more likely it’s a Zwift problem and not an individual problem. Maybe when they tweaked the code they broke something or they got a server issue they’ve yet to identify. I feel confident there’s more to this story. Any chance Zwift would comment again if you reached out to them?
I concur and have experienced the same. If this was only a port issue, then we would have been experiencing it previously. But for those of us who are all of a sudden experiencing it for the very first time, after years of no issues with no changes to the setup, it would seem to indicate an issue introduced by a Zwift change. Which is not to discredit any of the advice given that will obviously help those with the specific issue addressed in this article.
Harry, my past experience has been that Zwift support has much to improve, to put it very mildly. They usually send you pre-canned suggestions (which, granted, may be helpful, but not in all cases) and block all possibilities for “back and forth” discussions. Unlike Wahoo Fitness, where you can open a ticket and continue discussion until YOU chose to close it, Zwift closes the ticket once they replied (actually, there is not even a ticket, there is no number for you to refer to identify the history of past communications). They make it impossible to follow up. I do believe… Read more »
I feel like you are letting Zwift off of the hook here. Why are other video game platforms not having this issue. Why are Xbox and Playstation online games not having these issues? Also, wouldn’t this issue occur every time that you log into Zwift if network packet routing was the underlying issue?
I would not necessarily agree with that. While I do not play games, I read that games which heavily rely on online traffic (these would be multiplayer games) can be very heavily affected by UDP packets loss, and network stability is a very big deal for gamers. The exact level impact depends on how much traffic is required and how well the game is written, I suppose. To answer your second question, it is possible that UDP traffic may vary over time depending, in part, how many riders are near you or in the game at any given moment. It… Read more »
I run cabled network (500 mb), without firewall.
Have experienced drop out two times over the last 10 training days. Will I still need to update the computer’s firewall?
Steffen, I was describing my own case, but everyone’s hardware and software is different. Your firewall may be different from mine, and it may or may not be an issue in your case. If dropouts is not an issue for you, don’t fix what ain’t broke. If it is an issue, give it a try and see if it helps. If it does not help, you can always turn off that new rule. I am a little confused by you saying that you are running network without firewall, but then bring up a question about updating firewall. I assume, you… Read more »
Andrei, Is Zwiftalizer a little slow usually? I have a 66 MB log file I wanted to investigate but the website has been churning the information for about 5 minutes now.
I did not notice that, but I never had a 66 MB log file! Mine are usually under 2 MB. 66 MB sounds unusually large!
Btw I’m honored to be told by a PhD in solid-state physics what to do about my drop-outs. 🙂
Thank you, Ron!
Good article. I have a question Andrei. The first problem with the bridge… it was connected to the main router over Wi-Fi?
Yes. I have a corporate Cisco phone which has to be connected to the internet via ethernet cable. This was the reason why I had to use an extra router in the bridge mode. If I had ethernet routed through my walls, it would make this task much easier.
Andrei, as an engineer myself I salute your absolutely first class fault finding and your extremely clear description of the cause and the fix. The world needs more like you.
Thank you, Barry. I appreciate your kind words. This was a fun project!
This whole post ignores that almost everyone is going to be sitting behind a home router, which is a Network Address Translation (NAT) device and firewall in one. Changing the settings on the Windows firewall described above (the “Setting Up a Firewall for Zwift UDP Traffic” section) will make no difference if the issue is upstream at the connection into the house. This is almost always where the issue is, not on the Windows computer itself.
Read it again more carefully. The symptoms and problems that occur upstream, in wlan, and in Windows are different. He’s covered the bases.
ElegantFowl: He’s offering the solution of opening up the Windows Firewall, which is almost never the issue. If it is the issue, it’ll be logged in the Windows Firewall log. (Or if not, this can be enabled to see if this is the problem.)
If there’s anything within the user’s home network losing UDP packets it’s often the home router because the state table runs out of memory, dropping sessions on this floor.
Steve, you are right in saying that the issue may happen anywhere from Zwift servers to our home computing device. We have no control over anything that happens outside of our home. We can only try and squeeze every bit of performance from our home network. If the issue is upstream from our home modem, indeed, there is nothing we can do about it. If it is in our home, we can troubleshoot and make some improvements, if we find what can be improved. Every little bit counts.
Thank you for the analysis and explanation. Next up: unreliable Zwift Companion connectivity.
Zwift could really use some reengineering here: don’t expect reliable delivery over UDP is in network 101.
Many programs which have some level of resilience against data loss use UDP. UDP protocol has two advantages: it is faster, and it does not clog the network in case of data loss. Data loss, within reasons, can be ignored if the data that is sent are relevant only at the moment when the datagram is sent, and can be replaced with the next datagram. UDP is the standard protocol for audio/video conferening – Zoom, Webex, Microsoft Teams, you name them. If sound or video get garbled for a fraction of a second, it is UDP packets loss in action.… Read more »
UDP is stateless protocol. What table of states you are talking about?
It’s the firewall’s decision-making state table, not anything to do with the UDP protocol itself which is as you say stateless.
Hi Andrei, if the issue is on the users end; why are we seeing these issues now? Why has this not been an issue for years?
I strongly suspect that Zwift has never seen so many users zwifting at the same time, and they have never in the past seen mass events with over a thousand of people participating. This increased load on their servers, and requires that more data is passed over to end users. Just think about it, your local Zwift should get data about every rider in your neighborhood. Everything that you see in the “Zwifters nearby” pane and as riders on the screen has to be transmitted to your computing device over and over again multiple times per second. This can create… Read more »
Excellent article and very clear steps for what to do. Thanks Andrei
Hi, Thanks for the article. I have a new Windows laptop which cames installed with McAfee for a set period. I can’t seem to set-up new rules but there is an option under “Smart Advice and Advanced Settings” to check “enable UDP tracking” should I check this?
Will you be able to reply to my crash log file (sent on Saturday) and tell me how I can get Zwift operational on a laptop with Windows 8. (We’re having to use this laptop as Zwift app isn’t available for Asus Chromebook 🙁 ) Have restored it to factory settings and it still won’t run Zwift.
Nigel, not sure to whom you addressed this request. Did you upload your log to Zwift support web page? This site is an independent Zwift-related web site not affiliated with Zwift in any way. You are not communicating with Zwift support by posting here….
Using a Macbook Air, I had Zwifters disappear the other day. Any guidance on the need to modify Mac OS firewall settings, and if so how? Thanks!
Deek, I am so sorry, I have absolutely no knowledge of OS on a Mac, or iOS on any device, for that matter, but perhaps other Zwifters would chime in?
First, I had this all the time on my iPad 2. Zwift was of no help with canned answers.
I upgraded to an iPad 4 and issues went away.
I red in one of these posts some using a MacBook Air. I read zwift wouldn’t work on the laptop
Jack, I agree, Zwift is different from most other cycling apps in that it generates its graphics and all objects “on the fly”. This requires a significant computing power. Office-grade laptops optimized for Microsoft Office and web browsing might not be up to the task, due to a weak integrated graphics. Many people successfully run Zwift on laptops, but it should better be a mid to high range laptop, not an entry level one. Not every tablet and not every phone can run it, either.
Very interesting article. This problem appeared for me about a month or two ago, and has mostly gone away now, but note that I don’t run a firewall on my computer so there must be something else going on as well!
That was my point, too. There may be multiple factors, we have control only on what is going on in our home. When cumulative effect exceeds a certain (unknown to us) threshold, issues start. I suspect, improvements which you mentioned may be related to loading of Zwift servers. Initial stages of TdZ were super popular, but closer to the end it looked like some zwifters may have decided to bail out. Or perhaps Zwift improved something on their end. Or just paid for extra cloud servers… Who knows…
How do I fix this issue on my MacBook Pro?
Luke, you would have to use Google to find instructions, or wait for other Zwifters to chime in. I am not a Mac user.
Great article and, if you have feel comfortable with technical terms, easy procedure!!!
Thank you Andrei!!!
I have Norton 360 running on my windows PC so can’t figure out how to change the firewall to make the changes you mention for window defender firewall. Any ideas on how to do it. Thanks
One of the first hits in Google search was this link:
https://smallbusiness.chron.com/open-port-using-norton-internet-security-56687.html
Shouldn’t software like Zwift scan your computer and either notify you to open ports or open them for you? I’m still not sold on this being an individual problem.
If a program could scan firewall settings and open the ports it wants, the firewall would be totally useless. Any malware would be able to take over any computer and steal all data from it. Zwift is designed to be robust and run without internet connection (after login) or with unstable connection – both at the price of lack of other riders. My issue was not with a blocked port but with firewall periodically rejecting data packets because it could no longer associate them with a legitimate receiving program. This is a downside to a high default level of its… Read more »
How do I stop the same thing from happening with Apple TV?
I wanted to share an observation. I’m running Zwift on a windows pc. I don’t do this very often but I saw it happen last night and it reminded me that I thought I’d seen it happen before as well. I’m riding with Cadence for about 1.5 hours with no issues. I notice a friend is riding so on the companion app I go to “find riders” and type in his name. He comes up and I click on him. When I push the button “Fan View” I notice a “Glitch” in my screen and then riders start disappearing. In… Read more »
This has worked well so far!
ive had this issue on ZRL races, followed your advice and changed port. if this works i will be forever thankful cheers.
I run into this problem when I run Zwift on a new iPad. Last season I had no problems on an older iPad. Even now when I use the old iPad (without an update) everything runs as usual, reinstalling it on the new iPad hasn’t solved the problems. I wonder if others also experience this problem on an iPad.