USB screen looks weird

[Mawarii]

Hey everyone,

I tryed to fix the issue but i wasnt successful. I have no idea what I did wrong. Here is a picture, so maybe someone knows what this is.
I am pretty sure the resolution is not a problem. I tried that a couple of times in different ways.
Maybe I have to change smth in the code, but I dont understand it. I am pretty new in C programming. Would be awesome if anyone can help. I would love it.
Thanks for every reply :)

ps: strange is, that the most users have delay problems, but I dont. It would work perfectly, if I could see anything ^^