Generally, players will experience crashing when their device is running low on RAM (please note this is different from storage memory). In order to alleviate this crashing, please try the following workarounds all together, in this order. If the issue persists after completing a step, try the next one.

1. Restart your device. Press and hold the Sleep/Wake button until the red slider appears. Drag the slider to turn your device completely off. After the device turns off, press and hold the Sleep/Wake button again until you see the Apple logo.
2. Force close all of your open apps. Swipe your finger up on each of the apps you see to close them. Further help with this can be found here
3. Clear your cache.
4. Make sure you're on a stable internet connection, such as using Wi-Fi instead of cellular data.
5. Check if you are using the latest version of the app. If you're not sure if you have the latest update, please click here for steps on how to update your apps.
6. Free up storage space. You can do this by deleting unused apps, pictures, and videos on your device.