Have a Shield TV for the last year or so... love it in general other than the random general Android bugginess that has been there on every phone I ever had before switching to an iPhone.
The other day I went into YouTube and I was randomly not logged into my account. When I try to hit the sign in button in YouTube settings it says there was a problem signing into my account and the button disappears completely for a while. Eventually the button shows up again but still is broken when I try to sign in.
My google account is handled by Android TV settings and is working fine there. Everything else using that account (movies, music, etc) works fine.
Restarts don't help. Tried uninstalling the app but it won't allow me.
Any other advice?
Check out the thread here :
https://www.reddit.com/r/theNvidiaShield/comments/5vu467/youtube_kicked_me_off_my_account_and_wont_sign/
What worked for me was clearing YouTube data (not just the cache). Others reported success by going into settings and logging out of the account and then logging back in.