Authenticator app

Question

I bought a new phone yesterday and am currently trying to log in to my work and school emails but it needs a code from my authenticator app but it is going through to the old phone, which I traded in and don’t have access to. How can I log in to my accounts when this current app is not giving me the codes?

Answer 1

Hi @Emily Morrice

Regarding your issue, since the verification codes are still being sent to your old device and you no longer have access to it, this will need to be handled by your organization’s IT administrator. Please contact your work or school IT admin and ask them to reset or revoke your multi‑factor authentication (MFA) methods for your account.

They can follow these steps:   

1. Sign in to the entra.microsoft.com as at least Authentication Administrator.   
2. Select User -> All user.   Select the user (your account) to act on and select Authentication methods. then select Require re-register of multi-factor authentication.    

• Require re-register MFA: This disables all previous authentication methods. You'll then be prompted to configure a new MFA authentication method the next time you try to sign in, so you can set up from the start and add a new authenticator app.   

For more details, please refer to: Manage user authentication methods for Microsoft Entra multifactor authentication. 

Note: Once re-registration is triggered, all your existing MFA methods such as phone numbers, Authenticator app, or other verification options will be removed. You will need to set up new MFA methods during your next login. Please ensure you have access to a valid phone number or the Microsoft Authenticator app before attempting to sign in again. 

If you’re not sure who your school’s IT administrator is, you can follow the guidance here to find them: How do I find my Microsoft 365 admin?

Hopefully, they will be able to help resolve your issue effectively.

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Answer 2

Because the Microsoft Authenticator app on the old phone was last used, push notifications and approvals are still being sent there, which blocks sign-in on the new phone.

To regain access:

1. Use an alternative verification method (if configured)
   During sign-in, choose “I don’t have my Microsoft Authenticator app” or similar, then select another method such as SMS or email code if they are listed.
   • If codes are not arriving, follow the guidance under “I'm not getting my verification code. What do I do?” to check for blocking, junk mail, VOIP numbers, or incorrect security info.
2. Ask the organization’s IT/Help desk to reset MFA (work or school account)
   For work or school accounts, if no alternative method works and the old phone is gone, the organization’s Help desk or Microsoft 365/Entra admin must clear the MFA settings. After they clear them, the next sign-in will prompt to set up Authenticator again on the new phone.
3. If the old device is still accessible (for others in similar situations)
   When switching phones in the future, open Authenticator on the old phone and approve the sign-in there once, then:
   • Remove the old device from the account’s security info so notifications stop going to it.
   • Set up Authenticator on the new phone and confirm it works before trading in or wiping the old device.

If none of the above is possible and this is a business/education tenant where the user is the only admin, recovery must go through Microsoft’s Data Protection process via support, as described in the referenced Q&A answers.

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References:

• Microsoft Authenticator FAQs
• 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
• Microsoft authenticator sending me into a spiral - Microsoft Q&A
• Requesting a Tenant Admin MFA Reset - Microsoft Q&A