If the above suggestions don't work, we have highlighted other steps to resolve 2-step verification and account recovery issues for the following scenarios:
New phone, old phone number - Google Authenticator
Sign in to your account with your username, password, and 2-step verification code from your old device (if your old device doesn't have internet service, you'll need to connect to trusted wi-fi network)
Go to your Security Settings page
Regenerate your secret key (Note: regenerating your secret key will invalidate your old device tokens)
Scan the new secret key with your new Authenticator device