Over the weekend, an issue started in Power BI desktop for me. I create a new report, get data and then when pressing save, I get a login screen. I pick my org credentials and see the login happen via our authentication provider and then am presented with the 'pick a login' screen again. This will happen over and over. If I close the pick a login screen, the save happens, but the file name in Power BI is not updated, it remains 'untitled'. I am able to publish to the service.