I have signed out and deleted global account hence having issue with microsoft authenticator

Question

hi,

I have yesterday migrated all our mailboxes from Gmail to Microsoft office 365. While setting up accounts I must have signed out accidently and now having difficulties in setting up or logging in to mailbox because I cannot use Microsoft Authenticator. There is now an issue with data protection and I don't know how to get it resolved.

Answer 1

Since access to Microsoft 365 mailboxes is blocked by Microsoft Authenticator and the original sign-in method is no longer available, the recovery path depends on whether there is another admin in the tenant.

1. If there is another Global Administrator
   1. Ask that admin to sign in to the Microsoft Entra admin center (Azure portal).
   2. Go to Users → All users and select the affected user account(s).
   3. Open Authentication methods.
   4. Select Require re-register multifactor authentication.
   5. Next time the affected user signs in, they will be prompted to set up MFA again (e.g., re-add Microsoft Authenticator on the new device).
2. If there is no other Global Administrator (only one admin, now locked out) In this case, the tenant is effectively locked out and MFA reset must be done by Microsoft’s Data Protection/Tenant Recovery team.
   1. Call Microsoft support using the regional Customer service phone numbers - Microsoft Support line.
   2. When prompted by the IVR, clearly indicate:
      • Using Office 365 for business / company account.
      • Calling as the administrator.
      • There is no other admin in the organization.
      • Need to open a service request with the Data Protection team to reset admin MFA / tenant admin MFA.
   3. Work with the Data Protection engineer to verify tenant ownership (they may ask for business documentation and contact details).
   4. After verification, they will reset MFA or re-register at least one admin account so that access to the tenant and mailboxes can be restored.

If support is difficult to reach, an alternative used in similar cases is to create a temporary new Microsoft 365 tenant (trial), sign in as admin there, and use that tenant’s admin portal to open a support ticket requesting Data Protection assistance for the original tenant.

Once at least one admin account is recovered, add additional MFA methods (e.g., phone, alternate email) and at least one more Global Administrator to avoid future lockouts.

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References:

• 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
• Global Admin Locked out - Microsoft Q&A
• Microsoft authenticator sending me into a spiral - Microsoft Q&A
• Severity A Situation - Locked out of global admin account (MFA) - business down - Microsoft Q&A
• Requesting a Tenant Admin MFA Reset - Microsoft Q&A
• Back up your accounts in Microsoft Authenticator