During a migration from Google (Mail or GDrive), you are hitting the following error:
Error:”unauthorized_client”, Description:” Unauthorized client or scope in request.”, Uri:”
Error:”unauthorized_client”, Description:” Client is unauthorized to retrieve access tokens using this method, or client not authorized for any of the scopes requested.”, Uri:”
The Google feeds for the service account are incorrectly set.
Make sure you add all the necessary scopes to set the permissions.