Yes... Zorin OS does not include a group named "power." Have you installed then removed any software prior to this that might have introduced that configuration?
While not ideal, you could simply create a "power" group to satisfy that.
Or remove that group from the configuration in /etc/dbus-1
No software additions or uninstalls, it is a fresh install off the 18.1 iso from the site. I have created the power group just to see, but now it just fails with:
dbus.service: Main process exited, code=exited, status=1/FAILURE
I will try another reinstall from a fresh iso again, but not super hopeful...
Actually, I think this is a safe idea to try. A fresh install can work wonders.
Because this looks like a configuration issue and if it is a new install - reinstalling is the best first thing to try.