I have seen some reports lately where players run into issues with the 2.12 update due to using an older Android OS or version of Google Play Services.
In either case, here are some first aid troubleshooting steps to try:
1) Have you tried turning it off and on again?
- Very often cache issues can cause problems running apps. I know everyone thinks that this won't apply, but restarting the device should only take a few min, and helps eliminate this cause of error.
2) Are you sure it is plugged in?
- Check that you are logged in with your correct Google account in the Play Store. Disconnecting and re-connecting the account can fix issues, as often a sync fails after an OS or Store Update.
3) Take out the trash.
- As mentioned in step 1), cache issues often cause problems running apps.
You can force your device to clear the cache on GOOGLE PLAY SERVICES and GOOGLE SERVICES FRAMEWORK, both pre-installed apps on Android devices.
Go to your device's Settings menu and look for Apps. Select the above mentioned apps and then tap on Force stop, and then on Clear cache. Lastly, restart your phone.
4) Bring in the new.
- Check the App store for updates for "Google Play Services".
Here is a direct link that you can use:
Do not install third party apps with that name. Make sure the Developer is "Google Inc." before downloading.
I hope this helps narrowing the issue down - the above mentioned steps should help if sync or cache issues cause the problem, and help us make sure where this error comes from.