If Google Authenticator codes are't working properly on your device, it would be because the time on your Google Authenticator isn't synching properly.
Synching the time on Android devices
- 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.
Synching the time on iOS devices
For most carriers the time update is done over the network. In these cases, you'll need to contact your carrier for issues. Otherwise, you can set it and check manually.
- Go to the main menu on the Google Authenticator app.
- Click Settings.
- Click General.
- Click Date and Time.