# OPC UA Server/Connection - Authentication failed: User Source not found

**URL:** <https://forum.inductiveautomation.com/t/opc-ua-server-connection-authentication-failed-user-source-not-found/107669>\
**Category:** Ignition\
**Created:** [June 23, 2025, 11:50am UTC](https://forum.inductiveautomation.com/t/opc-ua-server-connection-authentication-failed-user-source-not-found/107669 "2025-06-23T11:50:32Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![fanselm](https://avatars.discourse-cdn.com/v4/letter/f/47e85d/32.png) [@fanselm](https://forum.inductiveautomation.com/u/fanselm)\
**Post date:** [June 23, 2025, 11:50am UTC](https://forum.inductiveautomation.com/t/opc-ua-server-connection-authentication-failed-user-source-not-found/107669/1 "2025-06-23T11:50:32Z")

</div>

Hello,

I'm having an issue configuring the loopback connection for the internal OPC UA Server. I configured an additional internal User Provider for the module and configured it on both ends, but cannot get it working:

```python
java.lang.IllegalArgumentException: User Source "2" not found.
at com.inductiveautomation.ignition.gateway.authentication.UserSourceManagerImpl.createProfile(UserSourceManagerImpl.java:730)
at com.inductiveautomation.ignition.gateway.authentication.UserSourceManagerImpl.getProfile(UserSourceManagerImpl.java:717)
at com.inductiveautomation.ignition.gateway.authentication.UserSourceManagerImpl.getProfile(UserSourceManagerImpl.java:87)
at com.inductiveautomation.ignition.gateway.opcua.OpcUaModule$setup$config$1$identityValidator$1.authenticateUsernamePassword(OpcUaModule.kt:273)
at org.eclipse.milo.opcua.sdk.server.identity.AbstractUsernameIdentityValidator.authenticateUsernameOrThrow(AbstractUsernameIdentityValidator.java:140)
at org.eclipse.milo.opcua.sdk.server.identity.AbstractUsernameIdentityValidator.validateUsernameToken(AbstractUsernameIdentityValidator.java:118)
at org.eclipse.milo.opcua.sdk.server.identity.AbstractIdentityValidator.validateIdentityToken(AbstractIdentityValidator.java:56)
at org.eclipse.milo.opcua.sdk.server.SessionManager.validateIdentityToken(SessionManager.java:745)
at org.eclipse.milo.opcua.sdk.server.SessionManager.activateSession(SessionManager.java:622)
at org.eclipse.milo.opcua.sdk.server.SessionManager.onActivateSession(SessionManager.java:484)
at org.eclipse.milo.opcua.stack.server.UaStackServer.handleServiceRequest(UaStackServer.java:313)
at org.eclipse.milo.opcua.stack.server.UaStackServer.lambda$onServiceRequest$10(UaStackServer.java:276)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.base/java.lang.Thread.run(Unknown Source)

```

My internal User provider is called 'local\_users\_module\_opcua', which is also configured - when changing it also does not create a different log entry - the User Source "2" stays.  
I also tried allowing anonymous connections, which also did not work.

Am I overseeing something? I cannot do much with this log entry alone. I did not run into issues configuring the rest of my User Configurations.

Thanks in advance 🙂

---

<div class="post-metadata">

**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [June 23, 2025, 11:55am UTC](https://forum.inductiveautomation.com/t/opc-ua-server-connection-authentication-failed-user-source-not-found/107669/2 "2025-06-23T11:55:39Z")

</div>

Have you tried restarting the module or Gateway yet?

---

<div class="post-metadata">

**Author:** ![fanselm](https://avatars.discourse-cdn.com/v4/letter/f/47e85d/32.png) [@fanselm](https://forum.inductiveautomation.com/u/fanselm)\
**Post date:** [June 23, 2025, 1:04pm UTC](https://forum.inductiveautomation.com/t/opc-ua-server-connection-authentication-failed-user-source-not-found/107669/3 "2025-06-23T13:04:25Z")

</div>

yep, that was preventable. Solved by OS restart - thought I had done that previously.  
Thank you