Changed phone and can't get code on authenticator anymore. How do I fix this?

Question

I have office 365 for business and I changed my phone recently. I no longer get the authenticator codes on my new phone. I am the admin. How do I fix this? I called Microsoft and they promised to call me back to authenticate me but never called back.

Answer 1

Hello @Peter Purnadi,

Thank you for reaching out.

Do you already have a support ticket number for this issue? If so, please share it with me and I’ll be happy to help check the current status for you.

As this information is sensitive and may contain personal or tenant‑specific details (PII), please send the ticket number via Private Message instead of posting it publicly. I’ve already opened a Private Message, so kindly click “View message” to check it and reply there.

Thank you for your cooperation, and I look forward to your reply.

Kind regards,

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Answer 2

Because the phone changed, the Microsoft Authenticator app on the old device is still the registered MFA method and the new phone is not yet configured. The fix depends on whether there is another admin who can reset MFA for the account.

1. If there is another global admin in the tenant
   • Ask that admin to reset the MFA registration so the methods can be configured again.
   • In Microsoft Entra admin center, they should:
     1. Go to Users → All users and select the affected admin account.
     2. Open Authentication methods.
     3. Choose Require re-register multifactor authentication.
   • After this, sign in again; the sign-in flow will prompt to set up Microsoft Authenticator on the new phone (scan QR code, approve sign-in, etc.).
2. If there is no other admin (only one global admin – the locked-out account)
   • This is a tenant lockout scenario. Only Microsoft’s Data Protection team can restore access.
   • Call Microsoft’s global customer service phone number from Customer service phone numbers - Microsoft Support and explicitly request a Data Protection team case to reset the admin’s MFA:
     • When the IVR asks what the problem is, say “Authenticator”.
     • When asked what product, answer “Office 365 for business”.
     • When asked if it’s an education or company account, answer “For companies”.
     • When asked if there are other admins, answer “No”.
     • Confirm that a service request is needed and that the call must go to the Data Protection team to reset the only global admin’s MFA.
   • Be prepared to provide tenant details and business documentation so they can verify identity and ownership before resetting MFA.
3. If phone/SMS is also configured but not working
   • If any alternative MFA method (phone call/SMS) still works, sign in using that method and then update security info:
     • Go to the Security info / Additional security verification page.
     • Remove the old phone or app registrations.
     • Add the new phone number and re-add Microsoft Authenticator on the new device following the prompts.

If Microsoft support did not call back, call again using the Data Protection flow above and clearly state that this is a sole global admin locked out by MFA so the case is routed correctly.

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References:

• I have a new mobile phone and I want to add it to MFA
• I have a new phone number and I want to add it
• Common problems with two-step verification for a work or school account
• 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
• I need to reset my mfa methods - Microsoft Q&A
• Microsoft authenticator sending me into a spiral - 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
• Can't use Azure Multi-Factor Authentication to sign in to cloud services after you lose your phone or the phone number changes
• You don't receive a text or voice call that contains the verification code for Microsoft Entra multifactor authentication

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