issure is in both debian and fedora template based appvms? Do other websites play videos? Can you play video at all like in media player like vlc? Disable flash if enabled.
what if you try that html only youtube extension and see if that works for the hell of it, even though you have flash disabled and it should be doing that in the browser, worth a shot.
there is also vlc plugin for firefox browser. vlc uses its own codecs don't think it installs anything for systemwide. You have to install gstreamer packages for that. Although you shouldn't need to to for youtube, but i had to install gstreamer1-libav to play mp4 streams, maybe installing some codecs would help you also even though you shouldn't have to.
This happens in all vms?
yes but the youtube html plugin is worth a shot. I don't know what he'd do for other sites though.
on another note I can't stream my usual sites either cause I have to install mp3 and mp4 codecs on this fresh install. ugh.