Microsoft Authenticator issue

For a Valencia College (work/school) account where Microsoft Authenticator was removed and reinstalled, the old registration must be cleared and MFA re-registered. Because the sign-in still prompts for the old Authenticator and there is no other verification method available, this cannot be fixed only on the device; an admin must reset the MFA registration for the account.

Use these steps:

1. Contact Valencia College IT/Help Desk
   Explain that the Microsoft 365/Entra ID account is locked in an MFA loop after deleting and reinstalling Microsoft Authenticator and that there is no access to the old app. Ask them to:
   • Require re-register multifactor authentication for the user account.
   • Remove or reset existing sign-in methods for the account.
2. Admin-side action (for Valencia IT staff)
   An administrator with access to the tenant should:
   1. Go to the Azure portal → Microsoft Entra ID → Users.
   2. Open the affected user.
   3. Under Manage → Authentication methods, select Require re-register multifactor authentication.
   4. Instruct the user to sign in again; they will be prompted to set up MFA from scratch.
3. User reconfigures MFA after reset
   Once the admin has required re-registration and the user can pass the initial sign-in (for example from a trusted device or temporary method configured by IT):
   1. Go to the Security info page (for example via the Additional security verification or My Account portal, as directed by IT).
   2. Remove any entries tied to the old phone or Authenticator registration.
   3. Add a new sign-in method and choose Authenticator app and/or Phone.
   4. Install and configure Microsoft Authenticator on the current phone following the prompts.

If there is no other administrator who can reset MFA and the only admin account is also locked by Authenticator, the institution’s IT must open a support case with Microsoft and request assistance from the Data Protection team to reset MFA for the tenant admin, then for affected users.

References:

• Use a screen reader to set up and troubleshoot multifactor authentication
• Can't set up MFA because five devices are already registered to use an authenticator app
• Common problems with two-step verification for a work or school account
• Troubleshoot problems with Microsoft Authenticator
• How Do I Regain Access to My Account After Losing Access to Microsoft Authenticator? (Urgent Request). - Microsoft Q&A
• Authenticator locked and cannot access at all after replacing phone - Microsoft Q&A
• I need to reset my mfa methods - 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
• Microsoft Authenticator FAQs