Description:

While testing the Tenant Capacity Management API from Postman, I followed Step 5 of the Power Platform authentication documentation to request an access token. The API call succeeds when using the username/password flow, but when using the service principal flow, the request returns a 403 Forbidden error and no information can be retrieved.

Reference:

• Programmability and Extensibility - Authentication - Power Platform | Microsoft Learn

The service principal flow requires RBAC role assignments.

Reference:

• Tutorial: Assign roles to service principals (preview) - Power Platform | Microsoft Learn

We confirmed with the engineering team that the current RBAC implementation supports only Environment Management and Governance APIs. We understand that the scope of API coverage will continue to expand over time as this capability evolves.