Black screen when entering a match

Every time I try to go into a match in UT it black screens and I can't do anything its just a black screen, it doesn't even connect to the match, I'm forced to alt+F4 and try again and lose my games and I have to do this like 5 or 6 times for it to actually work

Its been like this for a few months but now its happening pretty much every time I launch the game.

How do I fix this? its annoying and its making me lose games for no reason