Accessing Microsoft Teams Free using personal or organizational credentials
"Hi All - So I had the same problem. Error message popping up I went into the account info for my microsoft account - the one indicating alias and login preferences and I deleted my mobile number as a means of login. Then I went back into my account - checked that everything was updated and opened the desktop app - seems to have worked :)
I also changed my profile picture - don't know if this makes a difference.
Hope this helps"
This is from A. User's post here. and its works for some of us. must try