I can’t login after changing my iPhone

Changing to a new iPhone breaks existing Microsoft Authenticator sign-in codes unless backup and restore are set up. Use these steps depending on the situation.

1. If the backup from the old iPhone is not showing On the old iPhone (if still available):
2. Turn on iCloud services for Authenticator:
   • Enable iCloud Drive.
   • Enable iCloud Keychain.
   • Enable iCloud Backup.
   • In Saved to iCloud, find Authenticator and turn its toggle on.
3. Make sure Authenticator is updated to version 6.8.33 or later.
4. Open the Authenticator app at least once.

On the new iPhone:

1. Uninstall Microsoft Authenticator.
2. Reinstall Microsoft Authenticator from the App Store.
3. Open it and look for the iCloud backup to restore; the backup should now appear.
4. If “Authentication did not complete” or codes are not accepted
5. Make sure the Authenticator app is unlocked on the iPhone (enter device passcode/Face ID and ensure the app is not still locked).
6. Check notifications for Authenticator are enabled and not set to silent, so approval prompts appear.
7. Confirm the app is on the latest version.
8. Ensure the iPhone has a stable internet connection (try switching between Wi‑Fi and mobile data).
9. Verify the iPhone date and time are set correctly (automatic time is recommended).
10. If still unable to sign in

• If this is a work or school account, contact the organization’s IT admin and ask them to reset or require re-registering MFA for the account in Microsoft Entra so new Authenticator methods can be configured.
• If this is a business tenant and there is only one admin and that admin is locked out, contact Microsoft Support by phone and ask for the Microsoft Data Protection team to help regain access to the administrator account.

4. If Authenticator itself will not unlock on the new iPhone If the app remains locked even after entering the iPhone passcode, remove the Authenticator app from the device and reinstall it, then set it up again using the account’s sign-in and MFA flow.

References:

• Microsoft Authenticator FAQs
• Troubleshoot problems with Microsoft Authenticator
• 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
• I need to reset my mfa methods - Microsoft Q&A
• Cannot unlock the Autheticator - Microsoft Q&A
• Cannot authenticate with E-mail when logging into Microsoft Authenticator(iOS). - Microsoft Q&A
• Microsoft authenticator sending me into a spiral - Microsoft Q&A