Comment 7 for bug 1775999

I had that same issue with xubuntu after 18.04 upgrade. First install vino. Mine was removed on upgrade without any notice. Also even after installing vino, the command vino-preferences doesn't work. Here is an easy workaround. Install dconf-editor then open it and go to org-gnome-desktop-remote access and turn off encryption. There are also several other remote options you can set in dconf-editor. However until you install vino, the remote-access doesn't show in dconf-editor. I hope someone can explain what happened to vino-preferences.