Hi,
I agree tenant domain name shouldn’t be causing 403 error.
I am not sure if you are using client credentials or authorisation code grant type. When I tried with client credentials I got 403 error.
But when I tried the same with authorization_code as grant type it worked for me.
Please try with authorization_code and re-authorise the account. Hope this will help you, if you are already working with authorization_code and still facing 403 error, I might need more information to check the issue. As of now with provided permissions at app level and scope in account level there shouldn’t be any 403 error.
