Good connection, no PS network

Hello,


My internet is working fine. The signal strengh is good etc. but for some reason I can't connect to the PS network. I can surf the net and I even updated the system software a few hours ago. the message I keep getting after a long wait is: "connection to the playstation network has timed out." I read on some other site that disabling the media server connection helps, but now I get the message : "an error has occurred. You have been signed out" blah blah blah. Any ideas please?