There are many reasons why Apps crash. Many times it is due to memory use on your phone.

Please try the following: Clearing your Safari Web Browser Cache, Update the app, Making sure no applications are running in the background by pressing the “Home” button twice, and sometimes switching from Wifi to LTE\/3G\/4G helps as well (or vice versa).

If crashing continues, a final recommendation is to uninstall and re-install the App.