It may be because the time isn’t correctly synced on your Google Authenticator app.
To set the correct time:
On your Android device, go to the main menu of the Google Authenticator app.
Tap More (upper right-hand corner) > Settings > Time correction for codes > Sync now.
On the next screen, the app confirms the time has been synced. You should be able 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.