Login failure, Sever reports access denied

I am a student in the University. To access wireless internet we always log in to the local network. The system was upgraded recently and now we seem to be having a strange problem. When ever you have logged into the network and the network jams, you cannot log in again. You get a message that ACCESS DENIED. YOU ARE ALREADY LOGGED IN. I contacted the network administrator the problem seems to persist. Is there a setting in my computer that prevents me from automatically logging out when the network disappears? Even when you log out and refresh when the network comes back, you still get the same message, Access denied. What should i do?