On-premises SharePoint data sources breaking

Hey MAVIE ,

I ahve not heard of this or seen this before.  A url being case-sensitive is not somethign I am familiar with.  I am wondering if the Power BI Desktop version has it lower or upper case and the Service is trying to be identical???? Just a weird theory...I have not heard of that before.  You don't have a flow or anything involved as well (as that could be case sensitive in certain situations)?

Lastly, I would confirm that nothing has happened to the userid or to the URL itself on the SharePoint site (maybe they had alternate mapping???)?

If it is not any of those, your best bet might be to open a support ticket as this seems quite unusual.  If you do open a ticket, please let us know the results so we all can learn something!