I have two Roku 3 devices in my home. One is working fine with the same apps. The other one started giving me "The channel did not launch please try again later" error when I try to start YouTube or YouTubeTV. This started less than a week ago, with nothing obvious to trigger it. Other channels on the problem Roku are working fine. It's just the two YouTube channels that give me the message. I've gone through the remove channel, restart, reinstall channel sequence; I've left the unit unplugged for 15 minutes between a channel removal and reinstall; and, I've done a factory reset and reinstalled the channel. Nothing's working. At least it's not an intermittent problem. I don't think the software versions on the Roku or the apps have changed. Here's the info on the unit and the app:
Model: 4200X - Roku 3
SW version 10.5.0, build 4208-04
MicroSD card not installed, but probably never had one? (only 14 channels installed)
YouTubeTV is version 2.20 build 93005575