Marlin LCD Can't click

I have just uploaded the Marlin firmware my RAMPS 1.4 Board, but although the LCD I installed does display all expected things, I can't select anything. I pushed the knob but it just blinks and goes back to the same screen. There's only a tiny chance for the LCD to work properly. The only way to make it work most of the time is by pushing the knob while turning it counter-clockwise.

I would greatly appreciate any help.

I found out why, but now I have another problem. I'm trying to test the motors but nothing moves. On the LCD it says "endstops hit:Z" and keeps changing whenever I refresh it.