Fix authenticator error

This happens when Microsoft Authenticator is still active on the old phone. During sign-in, the push notification is sent to the device where Authenticator was last used.

To fix it:

1. If the old phone is still available at all, open Microsoft Authenticator on that phone and approve the sign-in.
2. After signing in, go to your security info page and remove the old phone’s Authenticator registration.
3. Add the new phone again as a sign-in method.
4. If the old phone is not accessible, choose a different verification method such as SMS, if that option is available.
5. If this is a work or school account and no other sign-in method is available, contact the IT admin or help desk and ask for MFA to be reset or for re-registration to be allowed.

If the account was restored from backup on the new phone, work or school accounts are not fully restored automatically. Only the account name is restored, and the account must be opened and signed in again. If the app shows "Sign in to add your account.", that is expected.

If notifications still do not arrive on the new phone:

1. Make sure Microsoft Authenticator notifications are enabled in the phone settings.
2. Make sure the phone is not in Do Not Disturb or Quiet mode.
3. Verify the device has internet connectivity.
4. Make sure the device date and time are set correctly or automatically.
5. If only one account is affected, remove that account from Authenticator and add it again.

For a new phone with MFA, the old phone entry can also be removed from the Additional security verification or Security info page, then the new phone can be added.

References:

• Microsoft Authenticator FAQs
• Use a screen reader to set up and troubleshoot multifactor authentication
• Transfer Microsoft Authenticator account entries to a new phone
• Troubleshoot problems with Microsoft Authenticator
• My old phone has broken so I can’t access the old authenticator app so now I can’t log in on the phone as I need the old phone to login which I broken - Microsoft Q&A