if power bi desktop was showing you data and can't see anything in power bi service then there could have been some issue in power bi setup, however fact that you're not seeing any data returned in power bi desktop and get 'table is empty' message in preview window would mean there is any to little chance anything could be wrong with power bi.
You need to go back and check things on Salesforce side. Perhaps something is changed there. Instead of report can you try salesforce objects and import them ?
If you still believe it is problem on power bi side, I would suggest to raise a support ticket with Microsoft and get it checked.