authenticator stuck in a loop

Question

have ben sucessfully using authenticator for a number of work and .gov services until i upgraded iphone. since that have been stuck in a loop and unable to install work email (m365) in outlook on iphone. authenticator tells me to enter a code from authenticator. have followed advice from copilot but no success. authenticator gives no other options. any ideas? thanks

Answer 1

The loop happens when Microsoft 365 is configured to require Microsoft Authenticator, but the app on the new phone is not yet registered for the account and there is no alternative MFA method available.

Use these steps depending on the account type:

1. If this is a work or school (Microsoft Entra) account and there is an admin

• Contact the organization’s IT/admin and ask them to reset the multifactor authentication methods for the account in the Microsoft Entra admin center:
  • Admin goes to https://entra.microsoft.com → Users → All users → select the user → Authentication methods → Require re-register multifactor authentication.
• After the reset, sign in again on the iPhone; the sign-in will prompt to set up Microsoft Authenticator from scratch (scan QR code) instead of asking for a code from the old app.

2. If this is a work or school account and there is no other admin (sole admin / tenant owner)

• A sole admin who is locked out must work with Microsoft’s Data Protection team via support to get MFA reset.
• Call Microsoft support using the regional Customer service phone numbers and clearly state:
  • This is an Office 365/Microsoft 365 for business account.
  • The caller is the only administrator.
  • The admin is locked out due to Microsoft Authenticator on a replaced phone and needs an MFA reset by the Data Protection team.
• If reaching a live agent is difficult, create a temporary trial Microsoft 365 tenant, sign in to its admin center, and open a support ticket from there requesting Data Protection help for the original tenant, then cancel the trial after resolution.

3. If this is a personal Microsoft account

• Use the account recovery and alternative verification options (backup email, SMS, etc.) when signing in. If no alternative method is configured and only Authenticator is required, recovery must be done through Microsoft’s account recovery flow and/or consumer support; forum moderators and tools cannot bypass this.

4. General Authenticator troubleshooting while testing sign-in When testing after the reset, also ensure:

• Authenticator is updated to the latest version.
• Notifications are enabled for Authenticator and not silenced.
• The device has a working network connection (try switching Wi‑Fi/mobile data).
• Date and time on the iPhone are correct.

If multiple failed attempts have already been made, Microsoft Entra MFA may temporarily block further attempts as suspicious activity; waiting and then trying again after the admin/Data Protection reset is required.

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References:

• Troubleshoot problems with Microsoft Authenticator
• Authentication did not complete
• How to add your accounts to Microsoft Authenticator
• Common problems with two-step verification for a work or school account
• Microsoft authenticator sending me into a spiral - Microsoft Q&A
• How Do I Regain Access to My Account After Losing Access to Microsoft Authenticator? (Urgent Request). - Microsoft Q&A
• I cant log in to my business account because it is requiring Authenticator app which I do not have - Microsoft Q&A
• Requesting a Tenant Admin MFA Reset - Microsoft Q&A