Hello,
Thank you for reaching out to the Microsoft Community and I'll be glad to assist you today.
1. Have you backed up your Microsoft account credentials to a Recovery account before changing your phone?
If you have previously added a Recovery account, select "Begin Recovery" on the Authenticator app and enter your recovery account credentials.
• You will be prompted to verify your identity through the Authenticator app.
• Select "I can't use the authenticator app right now," or choose "Show more verification methods."
• You can then use alternate verification methods, such as your phone number or email address, to confirm your identity.
You may sometimes be asked to reset your password. Once the password has been reset, select "Begin Recovery" again and add your account to the Authenticator app.
All of your previously added accounts will be linked to your Microsoft account again, and you will need to verify each account next. You can then select the account you would like to know the One-time passcode that is displayed on the authenticator to sign in with that account.
Reference:
Restore account credentials from Microsoft Authenticator-
https://support.microsoft.com/help/ce53096e-1e1...
Let me know if you still need more help.