That's a server side error, meaning the problem is on their end, not yours.
Every now and then you can get some stale cache in your browser that will keep feeding you the 404 page even after it's fixed, so if it persists for more than a day or two, try clearing your browser cache. If it still doesn't work, then there's probably some major meltdown going on with the server side software (or even hardware) for the site, and someone is either in way over their head, or whatever went wrong is one of those things that is just going to take a long time to fix.
I do not know where this belongs, if it is singular to Apple computers, but I'll give it a shot.
I belong to a forum which contains, among other things, blogs and discussions.
The past two days, I have had 3 instances of not being able to "go there" and instead get this message:
404. That's an error.
The requested URL
was not found on this server. That's all we know.