# Gateway Tag Change Event Stopped Working **URL:** \ **Category:** Ignition\ **Tags:** ignition81, vision\ **Created:** [August 25, 2025, 2:21pm UTC](https://forum.inductiveautomation.com/t/gateway-tag-change-event-stopped-working/110147 "2025-08-25T14:21:48Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Noah\_St\_Mark](https://avatars.discourse-cdn.com/v4/letter/n/7ab992/32.png) [@Noah\_St\_Mark](https://forum.inductiveautomation.com/u/Noah_St_Mark)\ **Post date:** [August 25, 2025, 2:21pm UTC](https://forum.inductiveautomation.com/t/gateway-tag-change-event-stopped-working/110147/1 "2025-08-25T14:21:48Z")
Hi Everyone, I have a project with three gateway tag change events that no longer work. I noticed when I save the project I get this error: **java.lang.IllegalArgumentException: missing event subscriber for an annotated method. Is com.inductiveautomation.ignition.gateway.script.GatewaySystemUtilities@2611d161 registered?** at com.google.common.eventbus.SubscriberRegistry.unregister(SubscriberRegistry.java:109) ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/4/f/4fbd64b64afca6f1fe57fa823e22d6204269971a.png) The screen is fully functional I can see the PLC tags changing but the gateway event is not triggering like it used to. These events used to work just fine. I don’t know what changed. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/1/c/1c8bea678e88e8e74a573733e9132fd330823db3.png) ---
**Author:** ![ryan.white](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/ryan.white/32/73193_2.png) [@ryan.white](https://forum.inductiveautomation.com/u/ryan.white)\ **Post date:** [August 25, 2025, 3:12pm UTC](https://forum.inductiveautomation.com/t/gateway-tag-change-event-stopped-working/110147/2 "2025-08-25T15:12:19Z")
Post the full stack trace here as preformatted text, see [Wiki - how to post code on this forum](https://forum.inductiveautomation.com/t/wiki-how-to-post-code-on-this-forum/77831). If possible, also post your code for the event, redacted as necessary, again as preformatted text to help others troubleshoot. ---
**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:** [August 25, 2025, 3:22pm UTC](https://forum.inductiveautomation.com/t/gateway-tag-change-event-stopped-working/110147/3 "2025-08-25T15:22:56Z")
Exactly which Ignition version are you using, and have you restarted the gateway since the problem started happening? You (and/or @bmeyers) should contact our support department so they can start an official investigation - there's evidently something wrong here, although apparently pretty rare. > [@IgnitionProjectManager Error Notifying listener about project update](https://forum.inductiveautomation.com/t/ignitionprojectmanager-error-notifying-listener-about-project-update/96736/2): > > A gateway restart fixed whatever the issue was. ---
**Author:** ![Noah\_St\_Mark](https://avatars.discourse-cdn.com/v4/letter/n/7ab992/32.png) [@Noah\_St\_Mark](https://forum.inductiveautomation.com/u/Noah_St_Mark)\ **Post date:** [August 25, 2025, 3:32pm UTC](https://forum.inductiveautomation.com/t/gateway-tag-change-event-stopped-working/110147/4 "2025-08-25T15:32:02Z")
I was forced to restart because the gateway event scripts weren’t firing. I am on the phone with tech support now. ---
**Author:** ![Noah\_St\_Mark](https://avatars.discourse-cdn.com/v4/letter/n/7ab992/32.png) [@Noah\_St\_Mark](https://forum.inductiveautomation.com/u/Noah_St_Mark)\ **Post date:** [August 25, 2025, 3:40pm UTC](https://forum.inductiveautomation.com/t/gateway-tag-change-event-stopped-working/110147/5 "2025-08-25T15:40:56Z")
I missed your question. We are running 8.1.35. ---
**Author:** ![Noah\_St\_Mark](https://avatars.discourse-cdn.com/v4/letter/n/7ab992/32.png) [@Noah\_St\_Mark](https://forum.inductiveautomation.com/u/Noah_St_Mark)\ **Post date:** [August 25, 2025, 3:43pm UTC](https://forum.inductiveautomation.com/t/gateway-tag-change-event-stopped-working/110147/6 "2025-08-25T15:43:15Z")
```python java.lang.IllegalArgumentException: missing event subscriber for an annotated method. Is com.inductiveautomation.ignition.gateway.script.GatewaySystemUtilities@2611d161 registered? at com.google.common.eventbus.SubscriberRegistry.unregister(SubscriberRegistry.java:109) at com.google.common.eventbus.EventBus.unregister(EventBus.java:254) at com.inductiveautomation.ignition.gateway.project.ProjectScriptManager.unregisterEventBus(ProjectScriptManager.java:107) at com.inductiveautomation.ignition.gateway.project.ProjectScriptLifecycle.createScriptConfig(ProjectScriptLifecycle.java:269) at com.inductiveautomation.ignition.gateway.project.ProjectScriptLifecycle.startupScriptConfig(ProjectScriptLifecycle.java:235) at com.inductiveautomation.ignition.gateway.project.ProjectScriptLifecycle.restartScriptConfig(ProjectScriptLifecycle.java:231) at com.inductiveautomation.ignition.gateway.project.ProjectScriptLifecycle.onResourcesModified(ProjectScriptLifecycle.java:733) at com.inductiveautomation.ignition.gateway.project.ProjectLifecycle$LifecycleResourceListener.resourcesModified(ProjectLifecycle.java:176) at com.inductiveautomation.ignition.common.project.AbstractProject.notifyResourceListeners(AbstractProject.java:351) at com.inductiveautomation.ignition.common.project.AbstractProject.updateEffectiveState(AbstractProject.java:153) at com.inductiveautomation.ignition.common.project.RuntimeProject.applyChange(RuntimeProject.java:274) at com.inductiveautomation.ignition.gateway.project.ProjectLifecycleFactory$1.lambda$updateOrStartAffectedProjects$5(ProjectLifecycleFactory.java:185) at java.base/java.util.ArrayList.forEach(Unknown Source) at com.inductiveautomation.ignition.gateway.project.ProjectLifecycleFactory$1.updateOrStartAffectedProjects(ProjectLifecycleFactory.java:165) at com.inductiveautomation.ignition.gateway.project.ProjectLifecycleFactory$1.projectUpdated(ProjectLifecycleFactory.java:143) at com.inductiveautomation.ignition.gateway.project.BaseProjectManager.doProjectUpdatedNotification(BaseProjectManager.java:1055) at com.inductiveautomation.ignition.gateway.project.BaseProjectManager.lambda$fireProjectUpdated$25(BaseProjectManager.java:1005) at com.inductiveautomation.ignition.gateway.project.BaseProjectManager.lambda$submitToQueue$22(BaseProjectManager.java:983) at com.inductiveautomation.ignition.common.util.ExecutionQueue$PollAndExecute.run(ExecutionQueue.java:239) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.base/java.lang.Thread.run(Unknown Source) ```