OT: xscreensaver doesn't work

[ToddAndMargo]

Hi All,

Fedora 27, x64 installed from Fedora-Xfce-Live-x86_64-27-1.6.iso
Xfce 4.12
xscreensaver-gl-base-5.38-1.fc27.x86_64
xscreensaver-5.38-1.fc27.x86_64
xscreensaver-extras-base-5.38-1.fc27.x86_64
xscreensaver-gl-extras-5.38-1.fc27.x86_64
xfce4-screenshooter-plugin-1.8.2-9.fc27.x86_64
xscreensaver-base-5.38-1.fc27.x86_64
xscreensaver-extras-5.38-1.fc27.x86_64
xfce4-screenshooter-1.8.2-9.fc27.x86_64

I can fire up Screen Saver preference, I can preview my screen saver, I 
set it for five minutes, no screen saver. HOW CAN I LIVE WITHOUT MY 
BOUNCING COWS!!???

How do I get my screen saver to work. It does work on
other machines running Xfce and Fedora 26.

Many thanks,
-T