I do not use PS2, however I do use Xbox Live and mainly only play MKA and thats it. Make sure all your cables are plugged in correct. I would reseat all the ethernet cables and power down your router/ps2/modem then turn it all back on it if it still says the server is down... Simply wait because they are doing maintanance on the server and it will be back up.

ok dont worry dude this crap happens to me all the time. all i do when it says that is just keep logging back in. once you get in a room you may only be able to fight once or twice before everybody is like inviable and the chat is completly empty at that time you log out then back on again. see if that helps. ; )