This might be because the time on your Google Authenticator app is not synced correctly. To make sure that you have the correct time:
- Go to the main menu on the Google Authenticator app
- Click Settings
- Click Time correction for codes
- Click Sync now
- On the next screen, the app will confirm that the time has been synced, and you should now be able to use your verification codes to sign in. The sync will only affect the internal time of your Google Authenticator app, and will not change your device’s Date & Time settings.