Getting 401 Unauthorized error code while calling an OIC integration from BIP report

Summary:

I have created an app-driven integration that has
- trigger REST connection with security policy: OAuth 2.0
- the REST trigger configures multiple resources
- media-type of response body: XML
- response payload format: XML Schema

- Configuring the data source under the Publisher Administration, the username and password were entered as the Client ID and Client Secret.
- The BIP data model uses the GET method.

The OIC integration itself can be called successfully using PaaS or Postman.
However, trying to fire it through a BIP report, it returns an error message "Error while processing authentication at Trigger. Failed due to - 401 : Unauthorized".