Firefox can't play youtube videos on youtube; only embedded on other sites or in email.
Since yesterday I can't access videos on youtube any more. The page opens as it should and I can see all the video information and all comments and video suggestions, but the player itself is only a black screen. There are no controls and no picture.
I can still watch the videos embedded on other sites or in email, but not directly on youtube.
It's definitely a Firefox-related issue, because I double-checked with Chrome and IE and everything worked fine with those browsers.