Connectivity between Sharepoint and PowerBI

Hi PowerBI Community,

I have been asked to the possibility of using a Sharepoint folder for sales people to 'dump' a spreadsheet into every month with their sales targets.  However, I've hit a brick wall straight away as I'm struggling trying to connect to the Sharepoint folder from PowerBI desktop.  I used the root level https://xxxxx.sharepoint.com/ to find my folders and use an organisational account to authenticate but receive the message attached on the photo.  Can anyone shed any light. Many thanks in advance