Did you or one of your teachers or admins upgrade their phone or switch to another phone for some reason and now can't pass the 2-factor authentication (2FA) check during sign in? Please follow the steps outlined in this answer to reset 2FA.
We often find that end-users don't always remember or accurately convey exactly what they have been doing online, making it hard to diagnose the real issue. Here are some tips for troubleshooting and helping your customers reset their password.