How to fix Authenticator “QR code already used” and the account on the Authenticator shows "Sign in"

I manage students' accounts. one account had problem with MFA. The student tried reinstalling the Authenticator, but still unable logon to Office 365. I disabled the MFA, but still ask MFA with Authenticator. So, I tried that account on my two Android phones. The authenticator app always said the “QR code already used” and the account on the Authenticator shows "Sign in". I click the account most times there was no action. some time I clicked the account, it pops up me "To set up Microsoft Authenticator, you will need to go to aka.ms/mfasetup on a web browser". It is in a loop situation and unable to make MFA works for this strange account. I tried enforcing, disable, block, unblock, none of them worked. I could not remove the account from the phone. I must use my phone to manage many accounts, I don't want to uninstall / reinstall the Authenticator.