A Microsoft app for iOS and Android devices that enables authentication with two-factor verification, phone sign-in, and code generation
Because the phone with Microsoft Authenticator was stolen and there is no other admin on the tenant, this is a tenant lockout scenario that cannot be fixed by self-service tools.
Use these steps to regain access:
- Since password sign-in still works but MFA cannot be completed, normal online recovery flows will not help; MFA registration must be reset by Microsoft.
- As the only administrator, contact Microsoft’s Data Protection team via the global customer service phone numbers and request an admin/MFA reset for the tenant:
- Call the number for the region from Customer service phone numbers - Microsoft Support.
- When interacting with the automated system, clearly indicate:
- The issue is with Authenticator.
- The product is Office 365 for business / Microsoft 365 for business.
- It is a company account.
- Confirm being an administrator and that there are no other administrators.
- Ask to create a service request and be routed to the Data Protection team for tenant recovery and MFA reset.
- If phone support cannot be reached or does not route correctly, create a temporary trial tenant and open a support ticket from there:
- Sign up for a Microsoft 365 trial tenant (any business/enterprise plan).
- In the new tenant, go to the Microsoft 365 admin center → Support → Help & support.
- Open a ticket explicitly stating:
- Being locked out of a different, existing Microsoft 365 tenant.
- The admin username and domain of the locked tenant.
- That this is a sole global admin MFA lockout.
- Request escalation to the Data Protection / Tenant Recovery team to reset MFA for the locked tenant.
- This trial tenant is only a channel to reach support; it will not give access to data in the locked tenant. Remember to cancel the trial after the issue is resolved.
Once Microsoft Data Protection verifies identity and ownership, they can reset MFA registration for the locked admin account so that Authenticator (or another MFA method) can be configured again.
References:
- 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
- Requesting a Tenant Admin MFA Reset - Microsoft Q&A
- Severity A Situation - Locked out of global admin account (MFA) - business down - Microsoft Q&A
- Common problems with two-step verification for a work or school account