A Microsoft app for iOS and Android devices that enables authentication with two-factor verification, phone sign-in, and code generation
Unfortunately, once you have overwritten the backup in the Microsoft Authenticator app by adding a new account, it is not possible to restore the previous backup. The app does not have a feature that allows for the recovery of old backups after they have been erased. If you are unable to access your old accounts due to this issue, you may need to reach out to each service provider for assistance in recovering access to those accounts. They may have alternative methods for account recovery, such as email or SMS verification.
References:
- How Do I Regain Access to My Account After Losing Access to Microsoft Authenticator? (Urgent Request). - Microsoft Q&A
- I have a Micrsoft business account and I am the admin and the only user registered under this account. I can't log in because i have replaced my phone and the authenticator doesn't work. - Microsoft Q&A