Cannot log in on Youtube iPad app I get an Authentication failed error when I try to log in to the Youtube iPad app. But the same username and password work on Youtube Safari and other browsers.
Do you have two-factor authentication enabled on your Google account? If so, you may have to create an application-specific password for the YouTube login.

http://support.google.com/youtube/bin/answer.py?hl=en&amp;answer=184968