Thank you for pointing me in the right direction. It was a problem with the Azure connection setup. The FluentSMTP setup documentation does not indicate that you must use the ID of the email that you want to use in FluentSMTP has to be the ID that creates the connection in Azure. That is the ID that needs to own the connection for it to authenticate for the correct token request in the FluentSMTP settings. I was using a different Azure admin ID to create the connection causing the failure and forbidden error.
