handy number

Because the phone number changed and sign-in keeps asking for the old number, recovery must be done through the Microsoft account security and recovery flows, not by changing the number after sign-in.

Use these steps depending on what still works:

1. If sign-in is still possible with password or another method
   1. Go to the Microsoft account security page: https://account.microsoft.com/security
   2. Under Security info / Recovery options, add the new phone number as security info.
   3. Verify the new phone number (code by SMS or call).
   4. After the new number is verified, remove the old phone number from Security info so it is no longer used.
   5. If prompted for a password during this process and only a passkey/biometrics was used before, first set or change the password at the same security page (Advanced security → Change password / Create password), then repeat the steps to add the phone number.
2. If sign-in is blocked because the old phone is the only security info
   1. On the sign-in or verification screen, choose I don't have any of these (or similar) when asked to confirm using the old phone.
   2. Follow the prompts to update backup security info and prove account ownership using other information.
   3. Be aware that changing all security info can trigger a 30‑day protection period during which some actions are restricted.
3. If this is a work/school (Microsoft Entra ID) admin account with MFA and the phone was lost/changed
   1. Another cloud services admin must reset the Multi-Factor Authentication settings:
      • Sign in to the cloud service portal as an admin.
      • Go to https://account.activedirectory.windowsazure.com/usermanagement/multifactorverification.aspx.
      • Select the affected account, choose Manage user settings.
      • Check Require selected users to provide contact methods again, then Save.
   2. After that, sign in again and register the new phone number in the MFA setup.
4. If this is a business tenant and there is only one admin and no access at all
   • Contact Microsoft support/data protection as described in the guidance for locked-out single admins so identity can be verified and access restored.

If verification codes are not arriving on any method, use the account recovery form and guided tools linked from the Microsoft account pages to regain access, then update the phone number in Security info.

References:

• Troubleshoot Microsoft verification code issues
• Can't use Azure Multi-Factor Authentication to sign in to cloud services after you lose your phone or the phone number changes
• I can't sign in to my Microsoft account
• Change the email address or phone number for your Microsoft account
• Help with "phone number is already used" in a Microsoft 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
• Having problems getting text codes to confirm my account - Microsoft Q&A
• I need to speak with a real person and it seems impossible. - Microsoft Q&A