# DataChannelServlet Error **URL:** \ **Category:** Ignition\ **Tags:** ignition81, vision\ **Created:** [April 4, 2024, 5:24pm UTC](https://forum.inductiveautomation.com/t/datachannelservlet-error/88362 "2024-04-04T17:24:37Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Travis\_Graham](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/travis_graham/32/53480_2.png) [@Travis\_Graham](https://forum.inductiveautomation.com/u/Travis_Graham)\ **Post date:** [April 4, 2024, 5:24pm UTC](https://forum.inductiveautomation.com/t/datachannelservlet-error/88362/1 "2024-04-04T17:24:38Z")
Multiple times each day, my system throws a DataChannelServlet error that is immediately followed by a disconnect & reconnect of every Vision client - 35 clients in total. This error appears in the log of my primary front end Vision server. The message states: "local='ignition-ignvisgw-master' method=doGet: No pending message was found with id '0'. Request was made from ignition-igntaggw-master" The log properties are coming from: **gan-remote-connection-id** ignition-igntaggw-master Hovering over the DataChannelServlet error displays the following, "metro.Transports.Websocket.Servlet.DataChannelServlet" When this occurs, the disconnect & reconnect is fairly quick. Any open screen's objects will simply turn red and then clear again. On the client side, the warning message that is logged is as follows: Message: Connection to Gateway lost, due to exception. Time: Thu Apr 4 10:48:48AM Severity: WARN Logger: com.inductiveautomation.ignition.client.gateway\_interface.GatewayConnectionManager Stack Trace: com.inductiveautomation.ignition.client.gateway\_interface.GatewayException: Read timed out     at com.inductiveautomation.ignition.client.gateway\_interface.GatewayInterface.newGatewayException(GatewayInterface.java:360)     at com.inductiveautomation.ignition.client.gateway\_interface.GatewayInterface.getResponse(GatewayInterface.java:556)     at com.inductiveautomation.ignition.client.gateway\_interface.GatewayInterface.sendMessage(GatewayInterface.java:292)     at com.inductiveautomation.ignition.client.gateway\_interface.GatewayInterface.sendMessage(GatewayInterface.java:287)     at com.inductiveautomation.ignition.client.gateway\_interface.GatewayInterface.invoke(GatewayInterface.java:967)     at com.inductiveautomation.ignition.client.tags.impl.GatewayTagInterface$GatewayProviderProxy.lambda$readAsync$0(GatewayTagInterface.java:340)     at java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(Unknown Source)     at java.base/java.util.concurrent.CompletableFuture$AsyncRun.exec(Unknown Source)     at java.base/java.util.concurrent.ForkJoinTask.doExec(Unknown Source)     at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(Unknown Source)     at java.base/java.util.concurrent.ForkJoinPool.scan(Unknown Source)     at java.base/java.util.concurrent.ForkJoinPool.runWorker(Unknown Source)     at java.base/java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source) Caused by: java.net.SocketTimeoutException: Read timed out     at java.base/sun.nio.ch.NioSocketImpl.timedRead(Unknown Source)     at java.base/sun.nio.ch.NioSocketImpl.implRead(Unknown Source)     at java.base/sun.nio.ch.NioSocketImpl.read(Unknown Source)     at java.base/sun.nio.ch.NioSocketImpl$1.read(Unknown Source)     at java.base/java.net.Socket$SocketInputStream.read(Unknown Source)     at java.base/java.io.BufferedInputStream.fill(Unknown Source)     at java.base/java.io.BufferedInputStream.read1(Unknown Source)     at java.base/java.io.BufferedInputStream.read(Unknown Source)     at java.base/sun.net.www.http.HttpClient.parseHTTPHeader(Unknown Source)     at java.base/sun.net.www.http.HttpClient.parseHTTP(Unknown Source)     at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(Unknown Source)     at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)     at java.base/java.net.HttpURLConnection.getResponseCode(Unknown Source)     at com.inductiveautomation.ignition.client.gateway\_interface.GatewayInterface.getResponse(GatewayInterface.java:450)     ... 11 common frames omitted This issue appears at random, sometimes only 5 minutes apart, but it's occurring about 15-20x each day. I've logged traffic on our network through various switches, but I am not seeing anything out of the ordinary when this issue appears in Ignition. Any insight is appreciated! ---
**Author:** ![Travis\_Graham](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/travis_graham/32/53480_2.png) [@Travis\_Graham](https://forum.inductiveautomation.com/u/Travis_Graham)\ **Post date:** [April 4, 2024, 5:31pm UTC](https://forum.inductiveautomation.com/t/datachannelservlet-error/88362/2 "2024-04-04T17:31:31Z")
Another item I should have mentioned... Oddly, I do not log any messages on my back end tag gateway (ignition-igntaggw-master) when this issue occurs. Only the front end vision gateway (ignition-ignvisgw-master) throws a log message. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [April 4, 2024, 5:44pm UTC](https://forum.inductiveautomation.com/t/datachannelservlet-error/88362/3 "2024-04-04T17:44:01Z")
Wow, that's ugly. I would not expect a GAN error to kill your Vision connections. You should definitely report this to IA support. The errors in the Vision clients are side effects of the gateway breakage--I don't think those traces are relevant (just the normally tag poll failing). ---
**Author:** ![Travis\_Graham](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/travis_graham/32/53480_2.png) [@Travis\_Graham](https://forum.inductiveautomation.com/u/Travis_Graham)\ **Post date:** [April 4, 2024, 5:58pm UTC](https://forum.inductiveautomation.com/t/datachannelservlet-error/88362/4 "2024-04-04T17:58:39Z")
Thanks for the response, Phil. I'll get in contact with IA support. ---
**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\ **Post date:** [April 4, 2024, 6:24pm UTC](https://forum.inductiveautomation.com/t/datachannelservlet-error/88362/5 "2024-04-04T18:24:53Z")
> [@pturmel](#): > > I would not expect a GAN error to kill your Vision connections I read it differently - I think something else is hiccuping _all_ network comms on this frontend gateway, so _both_ GAN and Vision are showing symptoms of that one root cause. I honestly can't fathom a path for a GAN interruption to affect Vision clients. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [April 4, 2024, 6:27pm UTC](https://forum.inductiveautomation.com/t/datachannelservlet-error/88362/6 "2024-04-04T18:27:13Z")
> [@paul-griffith](#): > > hiccuping _all_ network comms Oooo! Good point. ---
**Author:** ![Travis\_Graham](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/travis_graham/32/53480_2.png) [@Travis\_Graham](https://forum.inductiveautomation.com/u/Travis_Graham)\ **Post date:** [April 4, 2024, 6:32pm UTC](https://forum.inductiveautomation.com/t/datachannelservlet-error/88362/7 "2024-04-04T18:32:36Z")
Checking my GAN on both front end and back end gateways, I have \<4ms ping times between everything. Also, I don't have any connection events listed for any of the gateways' "details" when viewing them in the GAN. I was hoping I'd see a connection event corresponding with the diagnostic log messages . ---
**Author:** ![Travis\_Graham](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/travis_graham/32/53480_2.png) [@Travis\_Graham](https://forum.inductiveautomation.com/u/Travis_Graham)\ **Post date:** [April 4, 2024, 6:59pm UTC](https://forum.inductiveautomation.com/t/datachannelservlet-error/88362/8 "2024-04-04T18:59:52Z")
I opened an IA support ticket and will work through that channel for a resolution. I'll try to post back here with information regarding cause and resolution once they're known. ---
**Author:** ![Travis\_Graham](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/travis_graham/32/53480_2.png) [@Travis\_Graham](https://forum.inductiveautomation.com/u/Travis_Graham)\ **Post date:** [June 7, 2024, 4:42pm UTC](https://forum.inductiveautomation.com/t/datachannelservlet-error/88362/9 "2024-06-07T16:42:07Z")
After working with IA for a very long period, supplying log files, many discussions, I am told that this issue is was a bug that is fixed in 8.1.41. I haven't had the chance to fully test 8.1.41 to verify. ---
**Author:** ![Tyler\_Bennet](https://avatars.discourse-cdn.com/v4/letter/t/aeb1de/32.png) [@Tyler\_Bennet](https://forum.inductiveautomation.com/u/Tyler_Bennet)\ **Post date:** [October 21, 2024, 3:02pm UTC](https://forum.inductiveautomation.com/t/datachannelservlet-error/88362/10 "2024-10-21T15:02:53Z")
What version were you experiencing this on Travis\_Graham? ---
**Author:** ![Tyler\_Bennet](https://avatars.discourse-cdn.com/v4/letter/t/aeb1de/32.png) [@Tyler\_Bennet](https://forum.inductiveautomation.com/u/Tyler_Bennet)\ **Post date:** [October 21, 2024, 3:04pm UTC](https://forum.inductiveautomation.com/t/datachannelservlet-error/88362/11 "2024-10-21T15:04:05Z")
I think I'm showing this on **8.1.35** possibly. [pturmel] Any insight if that bug affects this version? ---
**Author:** ![Travis\_Graham](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/travis_graham/32/53480_2.png) [@Travis\_Graham](https://forum.inductiveautomation.com/u/Travis_Graham)\ **Post date:** [October 21, 2024, 3:53pm UTC](https://forum.inductiveautomation.com/t/datachannelservlet-error/88362/12 "2024-10-21T15:53:47Z")
I was on 8.1.32 at the time. I'm now on 8.1.43 and issue is resolved. ---
**Author:** ![Travis\_Graham](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/travis_graham/32/53480_2.png) [@Travis\_Graham](https://forum.inductiveautomation.com/u/Travis_Graham)\ **Post date:** [October 21, 2024, 4:21pm UTC](https://forum.inductiveautomation.com/t/datachannelservlet-error/88362/13 "2024-10-21T16:21:08Z")
I'd guess .35 is affected, since the fix wasn't completed until .41.