Where people here talk about trying a "new account," I'm not clear which you mean...
#1 - creating an entirely new Google/Gmail account, using that for a new YTTV subscription, and then doing TVE in Channels?
OR
#2 - creating a new Family member account ID within YTTV, and then using that new Family account ID within the Channels interface in order to attempt TVE authentication?
If I understand things right, each Family profile within YTTV carries its own individual set of Library/saved content. So if you go with a new YTTV Family profile, that means you're going to have to redo all of the recording selections you had in the underlying YTTV Admin account.
Thanks!