OAuth2 Client Credentials 401 in Python Requests for Genesys Cloud

Can anyone clarify why my Python requests library returns 401 when calling /oauth/token? I am automating E2E test setup for our custom agent desktop. The payload includes grant_type=client_credentials, valid client_id, and client_secret in the header as Basic base64(id:secret). Yet the response body indicates invalid credentials despite confirming the values in the UI.

  • Verified endpoint URL matches our org region exactly.
  • Tested the same credentials via Postman with immediate success.