How to log onto authentication app on a new phone

Question

I have a new phone, and am unable to log onto my account for work on the Authenticator app. I need a code from the app to get in, but can’t get in without the code. I tried calling 10 different numbers for support but the automated system can’t connect me with someone who can help. I really need this app for work. I can’t do my job without it. Does anyone have any ideas on how to get into my authentication app, or anyone that might be hiring since at this point I don’t know what else to do.

Answer 1

Use of the Microsoft Authenticator app on a new phone depends on whether there is another sign-in method available and whether this is a work/school (Microsoft Entra / Azure AD) account.

1. Try an alternative verification method

• On the sign-in screen where the Authenticator approval is requested, choose “Sign in another way” (or similar link).
• If any other method is configured (SMS, phone call, office phone, email, security key), select it and complete sign-in.
• After signing in, go to your Security info / Additional security verification page and:
  • Remove the old phone/Auth­enticator entry.
  • Add the new phone and reconfigure Microsoft Authenticator.

2. If the old phone is still available

• Install/open Microsoft Authenticator on the old phone.
• Approve the sign-in request there.
• Once signed in, follow the steps above to remove the old device and add the new one.
• Then install Authenticator on the new phone and add the account again as described in Download and install the Microsoft Authenticator app.

3. If there is no alternative method and no access to the old phone

• For a work or school account, contact the organization’s IT help desk or Microsoft 365/Entra administrator and ask them to reset MFA for the account:
  • In Entra admin center they can go to Users → [your user] → Authentication methods and choose Require re-register multifactor authentication so that MFA setup is forced again on next sign-in.
• If this is a business tenant and the account is the only global admin and is locked out, the tenant admin MFA reset must be handled by Microsoft’s Data Protection team via a support ticket, as described in the Q&A references:
  • Call the regional Customer service phone numbers - Microsoft Support line.
  • When prompted by the IVR, clearly indicate: “Authenticator”, “Office 365 for business”, “company account”, “administrator”, and that there is no other admin.
  • Ask to create a service request and be routed to the Data Protection team to reset the admin’s authentication methods.
  • If direct phone support cannot be reached, create a temporary trial Microsoft 365 tenant, go to its admin center, and open a support ticket from there explaining that access is needed to a different, existing tenant where you are the only admin.

4. If still signed in on a computer

• If there is an active session in a browser or desktop app, go immediately to the account’s Security info or Additional security verification page and:
  • Remove the old phone/Auth­enticator.
  • Add a new phone number and/or re-register the Authenticator app on the new phone.

5. If all methods are lost and no admin/help desk is available

• For a work/school account, only the organization’s admin or Microsoft’s Data Protection team can clear MFA settings. End users and forum moderators cannot bypass MFA.

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References:

• Use a screen reader to set up and troubleshoot multifactor authentication
• Microsoft Authenticator FAQs
• Migrate to a new iPhone for work
• 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
• Severity A Situation - Locked out of global admin account (MFA) - business down - Microsoft Q&A