Authenticator faliure issue

A missing third-party account can be recovered from a previously enabled Authenticator backup; without a backup, use that service’s alternative sign-in or account-recovery method and then register Authenticator again.

If Authenticator backup was enabled

Third-party one-time password accounts, including services such as Facebook and LinkedIn, are eligible for backup restoration. Restoration must be performed on the same device type: iOS to iOS or Android to Android.^1^

Android

1. Open Microsoft Authenticator.
2. Before signing in normally, select Restore from backup or Begin recovery.
3. Sign in with the personal Microsoft account originally used as the backup/recovery account.
4. Confirm that the missing account and its rotating code reappear.

If the recovery option is absent, Authenticator requires signing out of or removing the accounts currently in the app first. Do not do this until existing accounts and their recovery methods are documented, because restoring is not selective.

iPhone/iPad

1. Confirm that the device uses the same iCloud account that held the Authenticator backup.
2. Install and open Microsoft Authenticator.
3. The backed-up account names and eligible one-time password codes should appear.
4. If an account displays Sign in to restore your account, select Sign in and complete the requested verification.

If no backup exists or restoration does not recover it

An individual deleted entry cannot be undeleted directly inside Authenticator.^2^

1. Open the affected service—Google, Facebook, your bank, or another provider—in a browser.
2. On its sign-in page, select an option such as Try another way, Use a backup code, Send an SMS, or Account recovery.
3. After gaining access, open that service’s Security or Two-step verification settings.
4. Remove the missing/old authenticator registration if the service requires it, and choose to configure an authenticator app again.
5. In Microsoft Authenticator, select + → Other (Google, Facebook, etc.) → Scan a QR code.
6. Scan the QR code displayed by the service, enter the resulting six-digit code on its setup page, and save any new backup codes. Microsoft documents this registration flow for non-Microsoft accounts.^3^

If Authenticator was the only configured verification method and the service will not allow access, contact that service’s support or—for a bank—its official customer-support channel. Microsoft cannot reset two-factor authentication for a third-party account; recovery is controlled by that account provider.

References

1. Restore one-time password codes in Microsoft Authenticator | Microsoft Support
2. Accidentally removed account from authentication app - Microsoft Q&A
3. How to add your accounts to Microsoft Authenticator