The configuration of the external application is not correct based on your called method in Postman.
Perform these steps:
-
Go to
https://your_orchestrator_hostname/identity/management/externalApps
-
Delete the External App
- Add Application → Confidential application → Add Scopes: Orchestrator API Access → Application Scope(s): OR.Queues
Your external app should look in the end like below
Let us know if now works.