[Q] Contact app crashes topic

Hi
My GalaxyS5 is running Android Lolipop, and I don't know why, byt my "Contact" app crashes sometimes (once or twice a day).
Anyidea of how I could understand why it crashes ?

Thanks
Nico

[Q] YU YUREKA set individual contact ringtone topic

am unable to set individual contact ringtone.

could you help me in settings to do so