Today I had to turn off YT ad-blocking. The YouTube app on our iPhones/iPads completely failed. It was like the app had a seizure (flickering black video screen). The YT list included 321 entries and after turning ad-blocking off the YouTube app worked again. Never had any issues on the SmartTV, Roku app and Android phones. To fix the problem all I had to do is a reset (option 2) now it works again. I don't know if a certain googlevideo domain caused this issue or something else. Just wanted to let you know if anyone else experiences this problem.