Which version are you using?
Are you familiar with adb or logcat? It would be great if we could see some logs.
Questions that we always ask for this kind of issues:
Are you using a rooted device or a custom ROM?
If not - did you go back to a stock after having had a custom ROM?
Btw does it help to restart the device?
It was a custom 4.2 ROM that I then flashed a rooted stock 4.3 ROM.
Restarting does no good.
I have your bug report, I sent you a PM