Cant log into Authenticator, with unusual circumstances

There is no way to sign back into Microsoft Authenticator or recover its stored account credentials if both of these are true:

• The original backup/sign-in email account (******@nbn.net) is no longer accessible, and
• There are no other verification methods configured (no passkey, no alternate email/phone, no other MFA method, no recovery codes).

In that situation, support agents cannot restore the Authenticator data or bypass verification.

The only available options are:

1. Try to regain access to the backup Microsoft account (if it was a Microsoft account)
   • Use the Microsoft account sign-in helper to see if access to the backup account can be recovered: Sign-in helper.
   • If access to that backup account is restored, Authenticator credentials may then be restorable from backup.
2. Reconfigure MFA individually on each protected service
   • For each app or service that used this Authenticator account for sign-in, follow that service’s own account recovery process (for example, using their recovery email, phone, or support flow).
   • Once access to each service is regained, set up new MFA methods (which can include adding the accounts again to a fresh Authenticator instance).

If the backup account cannot be recovered and the services do not offer any alternative recovery path, access to those services may not be recoverable.

References:

• Restore account credentials from Microsoft Authenticator
• I can't sign in to my Microsoft account