My issue was I changed jobs and the couple of teams accounts I had signed in no longer existed, or i was not allowed to access anymore. The app loops the login screen and you can't get to the menu, the back button just causes the login screen to come up again, continuously. There is no way to go back and chose sign into a different acvount. It just gets stuck insisting you sign into an account that no longer exists.
To fix this I had to put the phone into flight mode and quickly while the app looped and freaked out, intermittently and very briefly showed the teams list and menu button. I had to be very quick to press the menu button to the chose the account to then sign out.
Oh and I had exactly the same problem with my new work phone where the previous user was still signed in.
Well done Microsoft, Teams really is garbage.
No way to delete the app data
No way to sign out/forget accounts
No way to add new account when an old account is signed in
Ridiculous persistent sign in loop
