No it's not down, it's up and there's 122 players as I write this. Check your router/firewall maybe, or if you modified anything to your files try to revert it to the way it was.
The server isn't down, if it were you'd see many posts in this thread:
link
And I was just 2x Ninjaed
omg still failed to connect server...i dload the latest patch..but still failed to connect...>.>
Are you sure you're using the correct login and password?