The error message is YouTube's terrible attempt at humor.It's a bonafide "500 Error".
The 500 Internal Server Error is a HTTP status code meaning that it can't be more specific about what the exact problem is. It's however a definite server-side error, so the problem is of YouTube itself.
But then a group of monkeys such as the Saiyans can take down an entire planet and in this case they are "specially trained" so the problem is usually solved quickly, if you know what i mean.
Usually when I've seen similar on the websites I run it's usually because either a server log is bunged-up with too much data, a line of code has gone wrong, or the version of PHP on the webserver has been changed to a newer version than the script was designed to run on.... for instance most scripts generally run on PHP 5.2 to PHP 5.6, but webhosts are transitioning to PHP7+ and often switch the directory to the newer version automatically, so you end up having to roll it back to a version the site script likes.