Share your experience!
try to contact youtube app developer.
Hi @Shafiq99 I'm sorry to hear about that. 
How often would you say this happens, is it every second video you are watching or every tenth? Does the sound continue to play and only the video freezes up? Or does it start to buffer the video and both sound and video stops?
Is there any difference if you connect your phone to a WiFi network or use mobile data depending on which you experience this behaviour with?
I would recommend rebooting your phone in safe mode and play a couple of Youtube videos depending on how often this happens.
Let me know how it goes! 