401 error "Invalid 'iss'/'sub'

API Platform
1

Now Resolved thank you - When trying to send via APIM to another Service, we get the following Error
BatchResponse: { “error”: “invalid_request”, “error_description”: “Invalid ‘iss’/‘sub’ claims in client_assertion JWT”, “message_id”: “rrt-3749860190245415121-c-geu2-2076975-46713802-1” }
Could someone hlep, is this that we are not autentication to APIM itself or the Service we are trying to reach?