That url corresponds to the user @foxnews: https://www.youtube.com/user/foxnews
I have a fix for this that I made about four weeks ago but it’s in the discover branch that’s due to launch at the beginning of January.
So here’s the URL you want to subscribe to: https://www.youtube.com/channel/UCXIJgqnII2ZOINSWNOGFThA
Once I launch the huge discover branch you’ll be able to subscribe to https://youtube.com/foxnews (note that lack of @ in the url) directly.