Here are some recommended steps on how to get the game to work properly on your device:
- Make sure your OS is running the latest version that it can handle
- Have at least 1 gb of free space on your device's hard drive
- Close any other apps that may be open when you try to play
- Power off your device for 30 seconds
If these steps don't work, try putting the device in Airplane Mode as a test -- but don't forget to disable this afterwards!
Also, please note that if the OS of the device has been altered, the game may react strangely when trying to play.