Authenticator App New and Old Phone

McNulty, Bonnie 0 Reputation points
2026-03-26T17:20:25.7266667+00:00

I have the Microsoft Authenticator app on my old phone and my new phone. I am signed into my account on my new phone but it was not send me the verification code on my new phone. It becomes more complicated when I try to sign into my college account because the phone number on my new phone is not the same as my old number. I don't take my old phone with me because it is dying and is becoming unusable. Why does my Authenticator app on my new phone not get the verification code even though the account is linked?

Microsoft Security | Microsoft Authenticator
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  1. AI answer

    2026-03-26T17:20:51.65+00:00

    During sign-in, Microsoft Authenticator sends the push notification to the device where the app was last actively used for that account. If the app is still active on the old phone, notifications can continue going there instead of the new phone, even though the account is visible on the new device.

    For the college account, there is an additional complication: the phone number used for MFA (calls/SMS) is still the old one. Until the security info is updated, verification prompts that use phone (text/call) will go to the old number, not the new one.

    To address this:

    1. If possible, use the old phone once more
      • Open Microsoft Authenticator on the old phone and approve a sign-in request.
      • After signing in, go to the account’s security/MFA settings and remove the old phone as an authentication method.
      • Reconfigure MFA so that the new phone (Authenticator app and/or new phone number) is added as the primary method.
    2. If the old phone is unavailable or unusable
      • Use any other verification method offered at sign-in (for example SMS to a working number, or email, if configured) to get into the account.
      • Once signed in, update the security info so that the new phone number and the Authenticator app on the new phone are set up.
    3. For a work or school (college) account
      • If no alternative method works and the old phone cannot be used, contact the college’s IT/helpdesk and ask them to reset MFA for the account. They can clear the old methods so the Authenticator app and new phone number can be registered again.

    Going forward, when changing phones or numbers, remove the Authenticator app and old phone number from the account’s security info and add the new phone/number so that notifications and codes are sent only to the new device.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

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