Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
Google seems to be futzing around with their YouTube channel lately. Each day as they fix one problem they seem to create another.
Meanwhile, did your system just update to Roku version 10 that is currently rolling out? (Settings / System / System update will tell you your Roku software version and when it was installed.)
If you've been updated to version 10, perhaps the YouTube app needs to be updated to be compatible. Or perhaps it has been updated but you just don't have it yet. You can forcean update to the current version of all your apps via Settings > System > System update.
Roku Streaming Stick +, 3810X, Ser YH0059427035, wifi - Samsung UN55ES6100
Roku Streaming Stick, 3600X, Ser 5S56D8240827, wifi - JVC EM37T