Just today I started hitting "This content isn't available. Try again later" pages whenever I visit a YouTube video page in my Helium browser with uBlock Origin. Some new developments in the ad wars perhaps?
It changes often. Verify you are on the latest version of uBlock then force an update for any of the ad-block and Unbreak sources in your uBlock config. If that does not work de-select all of them, restart the browser and enable one at a time to see when it breaks which may require restarting the browser each time to get reliable results.
Got same message in Chrome with uBlock Origin Lite when I clicked on an YouTube link.
Even worse sometimes when I'm in an Incognito window or after I've erased my browser history Google asks me to solve a captcha which made switch to DuckDuckGo for all my searches.
I got that about 2 weeks ago. Till new versions of the ad blockers appeared, I just used private browsing in firefox. Now I have updated all my ad blockers, seems to work OK..
Even worse sometimes when I'm in an Incognito window or after I've erased my browser history Google asks me to solve a captcha which made switch to DuckDuckGo for all my searches.