@kontrag you have asked this question ebfore and it was the same sort of discussions. The Error Event does not get support on a user task: BPMN Error event on User Task - How to correlate to the current instance, Raise BPMN error from a user task as a boundary event
You are receiving a Message from another system, which indicates the error.
If you were using a Intermediate Catch Event, you would not be trying to use a BPMN error for this. You would use a Message Catch event or a Receive Task