Blank screen while playing a video on web?

Hi! So I have youtube blocked in my country so I use a website called playit.pk to watch the youtube videos since I can't use a proxy here in the dorm either. So what happens is that on this website the screen of the player turns black. I can hear the voice but not see anything. And this just happens on this website and only with me. It works fine for my room mates and it also works fine for me on my iphone:/
Can anyone help me with the problem?

Right click video, options. Disable hardware acceleration.

That may just fix it.

Hidemyass is an online proxy anyone can use.

Hope it helps.