Azure AD - User unable to Register MFA

Issue: You have a user unable to re-register for MFA on their new/replaced device.

Cause: User's older/previous Authenticator App record is still active and needs to be deleted before they can re-register for MFA

Solution: Delete the Authenticator App entry for the user on their mobile device. This will allow their device to re-register for MFA on the authenticator app; or admin can delete the entry under "Authentication Methods" in user details in Entra ID.

Case 17485