Why has my youtube video completely frozen?

About a year ago my youtube video was about to hit 600 000 views and it had a load of comments, new ones coming in prettyh mcuh every day. I decided to fonally get round to sorting this out. Why did it stop getting comments and views and the view count completely frozen? There were no copyright claims or anything that I was notified of, it is just completely off the map on youtube, it seems, even when I search for the video it doesn't come up. Have a put some kind of setting on to freeze the video? It's annoying, if somebody has a solution please help me out, thanks.