My game keeps crushing

Hello All,
Hopefully you will be able to help me out. So my main issue is that since 8.3 has been launched I am experiencing that my screen freezes and the game stops , I can still kill or hear what I am doing, but cannot see as my screen would not move for 15-20 seconds or until a re-open the game. It is really frustrating. It mainly happens when I am killing daily quests in the Visions of N’Zoth and during mythic dungeons as well.
Hopefully , I will get some help! Many thanks in advance!