vncviewer cannot connect to server after the sever reset

Hello guys, I had an IBM machine running SuSe 8.1 and tried to connect to a vnc server through the command: vncviewer xxx.xxx.xxx.xxx. It can work at the first time. But as soon as the server reset and I ran the commmand again, nothing happens. the viewer cannot connect anymore. the message I always got is like: "authentication suceessfully. the server closed connection" Got any idea why this happens and how to fix it? Thanks in advance. Eric