Google Authenticator

Codes from Google Authenticator not working after phone reset

If you recently reset or wiped your phone, the Google Authenticator app might not be able to generate valid codes. To get your Google Authenticator app working again, you will need to delete your account from the app, turn off 2-step verification, turn it back on, and add your account to the app again.
Open the Google Authenticator app on your phone.
Delete your account from the app. Don't worry, your Google Account will not be deleted – just the connection from the app to your account.
Press and hold the account you want to delete, then tap Delete on the dialog box that pops up.
Go to your 2-step verification settings page.
Click Remove near your smartphone name (Android, BlackBerry, or iPhone).
Turn 2-step verification back on by clicking Set up 2-step verification and following the directions. You will need to configure Google Authenticator again on your phone, but your other details will be saved.
Once you've completed the 2-step verification setup, your app should once again be generating valid codes