It's not working for me either
VZW TP2 MR2 stock ROM.
HTC YouTube 2.6 build 2011.1727
when I click on a link in an email, the youtube app opens, and looks like its trying to play the video. I see the "Connecting" and then I get a pop up saying Connection failed. Please try again.
Connection is fine. I can open the youtube app and play videos and search etc.
Edit:
ok so it seems to work ok for some videos and not ok for other videos.
For example, it work ok with this link:
http://www.youtube.com/watch?v=ZbYmUpy7tmk
but I get the connection failed error with this link:
http://www.youtube.com/watch?v=CwE-SLnLkqY
I guess this could be the youtube app and not the integration app.