Please try the following steps in this case: 
1. Free up device memory by closing all applications running in the background.
2. Reboot your device and try starting the game again.
3. Don't let your storage get too full. Make sure that you have plenty of extra free physical space (at least 2 GB) above the actual program size for caching purposes.
4. Check if your device is using a reliable and secure connection (Wi-Fi or solid 3G/4G). If you are using only one connection method, try to use another one to check if the issue persists.