The Subscriptions feed error message is resolved for almost everyone. If you're still seeing it, know that it will be fixed soon – thanks for your continued patience! You can follow along here for any additional updates: https://yt.be/help/CBxM https://twitter.com/TeamYouTube/status/1119013035580878848 …
Sorry to hear about the trouble. Try uninstalling the YouTube TV app, restarting the device and reinstalling the app to see if that helps. Keep us posted.