sddm doesn't restart properly - error connecting to consolekit

[Holger Wagemann]

Hello dear Maintainer,

I've some trouble with sddm and plasma5.

I've a fresh installed FreeBSD 11.2, which is up-to-date, I use
only prebuild binaries of "latest" repo and have installed sddm,
plasma5-plasma-desktop and further stuff:

plasma5-plasma-desktop-5.12.5_3
sddm-0.17.0_2
consolekit2-1.2.1

On first login everything works like a charme but when I leave
plasma5-session and do a logout, then I get a black screen for a minute,
then sddm appears again but does not offer me buttons for shutdown
or restart. Sometimes the restart button appears after a while.

Switching with Strg+Alt+F1 on a terminal during time of black sreen
shows me following error message:
ck-launch-session: error connecting to consolekit

How to fix this? Meanwhile I can login per startx and a ~/.xinitrc but
I don't want mny wife to offer this way for starting her
plasma5-seission :-)

Kind regards
  Holger