I tried everything I could in Google account management to clear the 2FA on the account I created a month ago without success. My Google account told me that it had seen a suspicious login attempt and ask me to confirm that it was really me, but that didn't clear the problem. Even though I could logon to both YouTubeTV and Google without a problem thru my web browser, ChannelsDVR could not and failed every time.
Well, I was able this time to just delete the Google account I created a month ago, wait a half hour or so to make sure Google had deleted it completely, and then go back in and create a new account with the same email address and password I used last time. I then added it my main Google account as a new Family member, just like I did a month ago. AND GUESS WHAT... that fixed my problem. My YouTubeTV channels work again and I didn't have to delete the YouTubeTV connections I had set up in ChannelsDVR with my email address and password like I did last time. That made it much simpler than what I did last time.
Dave