Crash log: - "Terminated because there is no system application"

I am working on app.running on iOS 8.3 and XCode 6.3.1 Since my app accidentally crashes (usually not long after launch) and my iphone displays a black screen with a white apple logo. Like the loading screen, but only for a few seconds. Then the iphone goes back to the locked screen.

it works fine in simulator but gets crash when running in iphone.

early.