Standalone mode causing crashes and 5.3 rendering crash

I’ve converted my 5.2 project to 5.3 and whenever I play the game with my main Pawn Character, crashes with this (even normal play mode, nut standalone in my case), but when I simulate the project, it works OK. I Guess the problem is with my Pawn, But can’t figure out what, as it was completely working fine up until 5.2.