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📲 Setting Up MFA on a New Phone

Getting a new phone is exciting — but it also means you need to transfer your Multi-Factor Authentication (MFA) before you lose access to your accounts. This guide walks you through the process step by step.

Before You Wipe or Trade In Your Old Phone

Important: If you still have access to your old phone, the transfer process is much easier. Do this before you reset, sell, or trade in your old device.

Step 1: Install Microsoft Authenticator on Your New Phone

  1. On your new phone, download Microsoft Authenticator from:
  2. Open the app and sign in with your Microsoft 365 email address.

Step 2: Update Your Security Info

  1. On a computer or tablet (not your new phone), go to https://mysignins.microsoft.com/security-info.
  2. Sign in with your email and password.
    • If prompted for MFA, use your old phone or an alternate method (text message, email code) to verify.
  3. Click ”+ Add sign-in method”.
  4. Select “Authenticator app” from the dropdown and click Add.
  5. Follow the on-screen prompts:
    • Open Microsoft Authenticator on your new phone.
    • Tap ”+” then “Work or school account”.
    • Choose “Scan a QR code”.
    • Scan the QR code displayed on your computer screen.
  6. Approve the test notification sent to your new phone.

Step 3: Remove Your Old Device

Once your new phone is verified and working:

  1. Go back to https://mysignins.microsoft.com/security-info.
  2. Find the old Authenticator entry and click Delete.
  3. This prevents confusion with duplicate entries.

I Don’t Have My Old Phone Anymore

If you’ve already lost, broken, or traded in your old phone and can’t approve MFA prompts:

  1. Try signing in at https://login.microsoftonline.com.
  2. When prompted for MFA, look for “I can’t use my Microsoft Authenticator app right now” or “Sign in another way”.
  3. Choose an alternate method:
    • Text message to your phone number
    • Email to your recovery email address
    • Phone call to your registered number
  4. Once signed in, go to your security info page and add your new phone.

If no alternate methods work, you’ll need to contact eTop to reset your MFA.

MFA Keeps Prompting Repeatedly?

If you’re being asked for MFA every time you open Outlook, Teams, or other apps:

  • Make sure you check “Don’t ask again for 14 days” (if the option appears).
  • Ensure your device’s date and time are set to automatic — a clock mismatch causes MFA failures.
  • On your phone, open Authenticator and make sure the account is listed and not showing an error.
  • Try removing and re-adding your account in Authenticator.

Not Receiving MFA Codes via Text?

  • Check that your phone has cellular signal (SMS codes don’t require Wi-Fi).
  • Verify the phone number on your security info page is correct.
  • Check your spam/blocked messages folder.
  • Restart your phone and try again.

Need Help?

If you’re locked out and can’t use any of the above methods:

📧 Email: helpdesk@etoptechnology.com
☎️ Phone: 951-398-0021

We’ll verify your identity, reset your MFA, and help you get set up on your new device.

Category: Education → Self Help Guides → Microsoft 365 Guides → Microsoft Authenticator
Author: eTop Technology
Last Updated: March 2026