User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:32.0) Gecko/20100101 Firefox/32.0 (Beta/Release) Build ID: 20140830210550 Steps to reproduce: I am trying to see a video on youtube.com without flash, using Firefox 32 on Ubuntu 14.04. The video is available as HTML5. Actual results: Youtube tells me: "An error occured please try again later." youtube.com/html5 tells me, H.264 is supported. Firefox 29 had the same problem. Chromium plays the video correct. I have installed the extension "User Agent Switcher". When I change to the predefined user agent Googlebot, the video displays fine. When I create a new user agent idetically to Firefox 31 on Windows 64, where the video plays correct, the same error occurs. Something is wrong with the useragent and/or youtube? Expected results: The video should play with the default useragent.