We have advice for Samsung which may apply. This is NOT a cure. The industry made a mess here and with the launch of google's ChromeCast I see more complaints like this. Makes you wonder.
Your post is incomplete as no one knows if it ever worked.
Try the usual DNS of 126.96.36.199 and 188.8.131.52 and if there is a firewall in the router it has to be turned off. This advice is in the noted forum.
If this fails, why not make this a warranty or return issue?
Well, It will load, but the only thing I get is the usual fuzzy background & the YouTube watermark in the top right corner. Absolutely NO information, no sign in, nothing.
I can connect my phone via YouTube and it will display my iPhone's name at the top, but I still can't watch anything. It just churns and churns on my phone.
Netflix, Skype, and AccuWeather all work fine.
I have tried:
-exiting out of the internet on the TV
-resetting the router
-unplugging the tv
-removing the YouTube app (I can't actually delete/reinstall, though)
-there is no new update
What am I missing? Halp?