Generally, players will experience crashing when their device is running low on RAM (which is different from storage memory). In order to alleviate this crashing, please try the following methods:

1) Force-close all open apps. You can learn how to do this by searching for "How do I force close my app?" in our FAQs.
2) Restart your device by turning it off and then turning it on again.

If the crashing persists after following these steps, please contact us at describing what you were doing when the crashing occurred and if you saw any error messages.