Authenticator app issues

Dear @Jessica A,

Good day! Welcome to Microsoft Q&A forum!

Based on your description, I understand that you’re unable to sign in to your work account because multi‑factor authentication is still linked to your old phone that had Microsoft Authenticator set up. After receiving a replacement phone, you transferred your apps and wiped the old device, but you can no longer receive authentication codes. When you try to sign in, you’re prompted to enter a code from the Microsoft Authenticator app, creating a loop that prevents access. You’re looking for a way to disconnect or reset Microsoft Authenticator for your work account so you can sign in again.

Regarding this situation, your work account still expects approval from the original Microsoft Authenticator setup. Even though the app was transferred to your new phone, the secure authentication connection didn’t carry over. For security reasons, Authenticator approvals are tied to the specific device during enrollment, so when the old phone was wiped, Microsoft no longer has a trusted device to send codes to.

Currently, there are several ways to deal with this.

The simplest being if you're an end-user, please reach out to your IT administrator for assistance. If you’re unable to sign in due to a phone change, a new phone number, or issues receiving your authentication code, your IT administrator can help by updating your authentication methods or revoking and re-registering your authentication.  

Please note that this is a community forum where users help one another. We do not have control over user accounts, including login issues, password resets, or access changes.

For detailed guidance, ask your IT administrator to review the step-by-step instructions provided in the referenced article: Manage user authentication methods for Microsoft Entra multifactor authentication

Here's how to find your IT Admin: How do I find my Microsoft 365 admin? (please also kindly reach out to your colleagues, managers, etc. to see if they have the IT department contact) 

Here where thing could get a bit complicated:

If you're an admin, please check to see if there are other IT admins in your organization who can help you with the reset.

If you're the only admin, in this situation, the Microsoft Data Protection Team has tools and processes in place to verify identity and regain access to administrator accounts.

Please let me know if you're the only admin of your organization so that I could provide you with suitable steps accordingly.

Any updates you’re able to share would be really helpful.

I'm here and happy to help! Thank you for your kindness and patience!

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To disconnect Microsoft Authenticator from a work account when the app on the new phone is not working, the account’s sign-in methods must be reset from outside the app. This cannot be done only from the new phone.

Use these options in order:

1. Try an alternative sign-in method (if one exists)
   When prompted for the Authenticator code on the PC:
   1. On the sign-in screen, tab or click until the option like “Sign in another way” appears, then select it.
   2. Choose another method (for example, SMS, office phone, or email) if it is listed, and complete sign-in using that method.
   3. After signing in, go to the Security info page for the work account and update or remove the Microsoft Authenticator method, then re-add it on the new phone.
   If no alternative method is configured, this option will not appear and an admin must reset MFA.
2. If this is a work/school account and there is an IT/admin team
   Ask the organization’s IT help desk or Microsoft 365/Entra administrator to reset MFA for the account:
   1. Admin signs in to the Microsoft Entra admin center.
   2. Goes to Identity → Users → All users.
   3. Selects the user account.
   4. Opens Authentication methods.
   5. Clicks Require re-register multifactor authentication.
   After this reset, the next sign-in will prompt to set up Microsoft Authenticator again on the new phone (scan QR code, approve sign-in, etc.), effectively disconnecting the old Authenticator registration.
3. If this is a work/school account and there is no other admin
   If the account is the only administrator in the tenant and there is no one else who can reset MFA:
   • Contact Microsoft via the regional Customer service phone numbers - Microsoft Support and request the Data Protection team to reset MFA for the tenant admin account.
   • During the call, clearly state:
     • This is an Office 365/Microsoft 365 for business work account.
     • The phone was replaced and the Microsoft Authenticator app on the old phone is no longer available.
     • The account is the only administrator and cannot pass MFA.
   • The Data Protection team will verify identity and can reset the MFA configuration so Authenticator can be set up again on the new phone.
4. General Authenticator troubleshooting on the new phone (after MFA is reset)
   Once an admin or Microsoft has reset MFA and sign-in is possible again, ensure the new phone is correctly set up:
   • Install the latest Microsoft Authenticator version and enable App updates.
   • Turn off battery optimization for Authenticator and ensure Show notifications is enabled in Notification Settings.
   • Make sure device date/time and network (Wi‑Fi or mobile data) are working correctly.

There is no way from the user side to “disconnect” Microsoft Authenticator from a work account without either using an alternative sign-in method or having an admin (or Microsoft Data Protection) reset the MFA/Authenticator registration.

References:

• Use a screen reader to set up and troubleshoot multifactor authentication
• Troubleshoot problems with Microsoft Authenticator
• Microsoft authenticator sending me into a spiral - Microsoft Q&A
• 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
• Microsoft Authenticator app doesn't show 6-digit OTP code - Microsoft Q&A
• Requesting a Tenant Admin MFA Reset - Microsoft Q&A