We couldn't authenticate with the credentials provided

Hello,

since 10/13 all my PowerBI reports stopped syncing in the Power BI Service and I cant authenticate anymore both in Service and Desktop versions.

We have an Office 365 subscription with two accounts, an Office 365 ProPlus and an Office 365 Business.

These reports have been going for more than a year, refreshing automatically every day. Data is on an Excel workbook online, in Power BI I used .SharePoint commands to get the files, and it always worked flawlessly.

The funny thing is that even in PowerBI Dekstop, reports don't refresh because my credentials are refused. I have been developing on these .pbix files for months so I am really scratching my head.

Once in Query Editor, I edit credentials and select Microsoft account, I sign in (correctly) and press Connect after it says "You're currently signed in". I see activity in the lower left corner, it connects and downloads something (in my case is 1,4 MB).

After this it fails, displaying the yellow banner with the text "We couldn't authenticate with the credentials provided".

I can tell you that I am currently working for several organizations at the same time, and I frequently switch between accounts.

Moreover I recently upgraded Power BI Desktop to version: 2.51.4885.701 64-bit (october 2017).

Other than this I didn't make any changes, and many old .pbix files stopped working even though I haven't worked on them for months.

Thanks for the help,

andreucci