Issue connecting published report to on-premis Access database.

Hi.

I have a user who is starting out with Power BI, he is the first to use this and I have been helping as best I can. He is trying to generate a report from an Access Database that is on-premis and publish it to the cloud and share it with others to view. The user has created the report and can connect to the database with the desktop application when he is on the corporate network or via VPN but as soon as it is published, he gets various sync errors. We have installed the gateway to the same PC as the database and set it in its default mode and on the face of things, the gateway connection is established.

Initially, the error was scheduled sync is disabled due to one data source not having credentials provided. We granted access as admin and it appears to all be green (below).

Now when we try to schedule a sync, the error we are getting is unspecified error, DataFormat.Error.

We are struggling to understand why the report renders correctly when we are connected using the desktop app but when published it appears to be a format error, the connection also appears to be stable and configured correctly.

Please advise!