This issue typically can be fixed by updating the app.
1) Tap the App Store icon on your iOS device's Home screen to launch the App Store app.
2) Tap “Updates” to show all available updates for the apps you have installed on your iOS device. Find your game on this list and tap the “Update” button.
3) You may be asked for your iTunes password or e-mail address and password. Type them into the relevant fields and click the “OK” button.
4) Wait. Messages will appear as the update completes, starting with “Waiting”, followed by “Loading” and, finally, “Installing.” When the status bar is filled and the app icon returns to normal, you can use your updated app.
1) Tap on the Google Play Store icon on your device.
2) Tap on the "hamburger" icon (three horizontal lines) in the top left to open the menu.
3) Select "My Apps"
4) Find your app and press "Update"
5) Wait. Messages like "Downloading" and "Installing" will appear as the update completes.
6) Try running the game once again to see if the problem persists.