I have had this for Firefox for over a year with no problems but since Sunday it has been blocking Youtube. Not just the ads it has been preventing the videos themselves from playing. I was getting nothing but error codes. So after trying everything and discovering there was nothing wrong my PC and noticing that Youtube videos were playing fine on Yahoo and any other websites that had them I decided to switch of my Ad Blockers to see what happens. So I turned of Ad Block and discovered it was blocking Youtube. So now I have it disabled on Youtube. Luckily I have uBlock Origin and Ad Blocker for Youtube installed.