Unable to login to microsoft. Faulty Authenticator function

The error indicates that Microsoft Entra multifactor authentication (MFA) is blocking sign-in because the verification step is not completing successfully. When this happens repeatedly, additional attempts may also be temporarily blocked as a security measure.

Since the user is stuck in a loop at sign-in and cannot complete the Authenticator step, resolution requires admin or support intervention rather than changes on the device itself.

Use these steps:

1. Wait or use another MFA method
   • Microsoft Entra MFA can block repeated attempts when it detects unusual activity. If there have been many failed attempts, wait and then try again.
   • If another MFA method is configured (SMS, email, security key), select that method at sign-in instead of the Authenticator app.
2. Check Authenticator issues on the phone If the error shown is “Authentication did not complete,” verify on the user’s device:
   • Ensure the Microsoft Authenticator app is unlocked.
   • Ensure notifications are enabled and not silent.
   • Update the app to the latest version.
   • Confirm the phone has a working internet connection and correct date/time.
3. Ask the organization’s IT admin / Help desk to reset MFA
   • For a work or school account, an IT administrator must reset the user’s MFA settings in Microsoft Entra so the user can re-register MFA on the device.
   • The admin should review Microsoft Entra sign-in logs to confirm whether the failures are due to misconfigured MFA or security blocks.
4. If the user is the only admin on the tenant
   • If this is a business tenant and the affected user is the sole global administrator, contact Microsoft’s Data Protection team via the global customer service phone numbers and request an admin MFA reset for the tenant.
   • If the subscription is through a partner/reseller, the partner can open a support request on behalf of the tenant.
5. Removing the requirement entirely
   • Disabling MFA or changing sign-in policies must be done in Microsoft Entra / tenant configuration by an administrator. It cannot be removed from the Windows startup screen alone when the device is joined to an organization and requires cloud MFA.

If these steps fail and no other admin can reset MFA, the only path forward is to work with Microsoft support (Data Protection team) to verify identity and reset the admin/user authentication methods.

References:

• Common problems with two-step verification for a work or school account
• Troubleshoot problems with Microsoft Authenticator
• Authenticator Did Not Complete Login
• 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 sending me into a spiral - Microsoft Q&A
• Requesting a Tenant Admin MFA Reset - Microsoft Q&A