New phone- Authenticator code on old phone

Question

I got a new phone and no longer have the old one that my Authenticator app was hooked up to. Everytime I try to log into the Authenticator app on my new phone it won’t let me in without entering a code from the old phone. I cannot access my school account now on Canvas which is the app/website all my classes go through. Please help me out if you can. I have assignment due tonight that I can’t complete without getting in.

Answer 1

Dear @Crysta Cluchey,

Good day! Welcome to Microsoft Q&A forum!

Based on your description, I understand that you recently got a new phone and no longer have access to the old device where your Microsoft Authenticator app was set up. When you try to sign in on your new phone, you’re being asked to enter a code from the old device, which you can’t access.

I sincerely apologize for the inconvenience caused by this issue.

Regarding your situation, this occurred because the Authenticator app wasn’t backed up or transferred to the new phone before the old device became unavailable.

Therefore, if you're an end-user, please reach out to your IT administrator for assistance. If you’re unable to sign in due to a phone change, a new phone number, or issues receiving your authentication code, your IT administrator can help by updating your authentication methods or revoking and re-registering your authentication.  

Please note that we have no control over user accounts, especially when it comes to logging in to your account, resetting your password, changing your access, etc.  

For detailed guidance, ask your IT administrator to review the step-by-step instructions provided in the referenced article: Manage user authentication methods for Microsoft Entra multifactor authentication

Here's how to find your IT Admin: How do I find my Microsoft 365 admin? (please also kindly reach out to your friends, professors, etc. to see if they have the IT department contact) 

As much as I’d like to assist you directly, only your school/organization's IT administrator can reset or update the authentication settings for your account. Please reach out to them for further help, as they have the necessary access to resolve this issue.

In the future, enabling cloud backup in Microsoft Authenticator and adding at least one additional MFA method (such as SMS or backup codes) will help prevent being locked out again.

Kindly let me know when there are updates or if you need further assistance. Any updates you’re able to share would be really helpful.

I'm here and happy to help! Thank you for your kindness and patience!

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Answer 2

Because the old phone with Microsoft Authenticator is no longer available and the app on the new phone is asking for a code from the old device, the existing Authenticator registration cannot be reused. The account’s MFA methods must be updated or reset outside of the app.

Use these options, depending on what is available for the school account:

1. Try other verification methods

• On the sign-in screen where Authenticator is requested, choose the option like “I can’t use my Microsoft Authenticator app” or “Use a different verification option.”
• If SMS or phone call is configured, select that method to complete sign-in.
• After signing in, go to the security verification page for the account (for Microsoft 365 school accounts this is the Additional security verification page) and remove the old phone and Authenticator registration, then add the new phone and reconfigure Microsoft Authenticator.

2. If SMS/phone or other methods do not work

• For work or school accounts where only Authenticator is configured and the device is lost, an admin must reset MFA for the account.
• Contact the school’s IT/help desk or Microsoft 365/Entra ID administrator and explain that access to Microsoft Authenticator was lost with the old phone and that MFA needs to be reset so the account can be re-registered on the new phone.

3. After MFA is reset or another method works

• Sign in to the account.
• Go to the security verification / Security info page and:
  • Delete the old phone/Authenticator entry.
  • Add a new sign-in method (phone and Microsoft Authenticator on the new device).
  • Install and configure the Microsoft Authenticator app on the new phone following the standard setup instructions.

If this is a school-managed account and there is no working backup method, only the school’s IT or tenant admin can clear or reset MFA so the account can be used again.

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References:

• Use a screen reader to set up and troubleshoot multifactor authentication
• Microsoft Authenticator FAQs
• Troubleshoot signing in with a passkey
• 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
• Cannot authenticate with E-mail when logging into Microsoft Authenticator(iOS). - Microsoft Q&A
• How Do I Regain Access to My Account After Losing Access to Microsoft Authenticator? (Urgent Request). - Microsoft Q&A
• Severity A Situation - Locked out of global admin account (MFA) - business down - Microsoft Q&A
• Requesting a Tenant Admin MFA Reset - Microsoft Q&A