Fedora 28+ removed the needed gtk-vnc-python package.
You can use the one from F27 by doing this as root:
rpm -i --force --nodeps http://dl.fedoraproject.org/pub/fedora/linux/releases/27/Everything/x86_64/os/Packages/g/gtk-vnc-python-0.7.1-3.fc27.x86_64.rpm
(change to i686 if you are still use 32bit, which you shouldn't)
Fedora 28+ removed the needed gtk-vnc-python package.
You can use the one from F27 by doing this as root:
rpm -i --force --nodeps http://dl.fedoraproject.org/pub/fedora/linux/releases/27/Everything/x86_64/os/Packages/g/gtk-vnc-python-0.7.1-3.fc27.x86_64.rpm
(change to i686 if you are still use 32bit, which you shouldn't)