Hi there,
403 typically means the user is authorized but is not allowed to perform the request. The server recognizes the user but the user is trying something for which they don’t have permission. Usually, a scope is missing, or their account type is limited (they’re not an admin/their role in the external application is not allowed to do that). Might be related to connection setup or to external settings.
You may need to reach out to the external service to get help on this.
Hope this helps! 