Ubuntu, a popular open-source Linux operating system, includes a Virtual Network Connection (VNC) program. The VNC program is used to access the Ubuntu computer from a remote computer, as well as to connect from the Ubuntu computer to other computers. If the program runs for a long enough period of time, it may cease to work. You must restart the program for it to function normally.
Log in to Ubuntu as the root user. If you can't log in as root, log in as a normal user, open a Terminal and then type "su." Enter your root password to gain root privileges.
Open a Terminal window, type "vncserver -kill" and press "Enter" to stop the VNC service.
Type "vncserver" and press "Enter" to restart the VNC service.