No kscreen backend found

[xargs]

I've added a third monitor to my system, and ran the Displays app in System Settings to configure it. Rather than seeing the monitor layout, I just get the text "No kscreen backend found. Please check your kscreen installation." The monitor does show up in the xrandr output.

> kscreen-doctor --info                                           
Environment: 
* KSCREEN_BACKEND           : [not set]
* KSCREEN_BACKEND_INPROCESS : [not set]
* KSCREEN_LOGGING           : [not set]
Logging to                : [logging disabled]
Preferred KScreen backend : KSC_XRandR.so
Available KScreen backends:
* KSC_Fake.so: /usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kscreen/KSC_Fake.so
* KSC_KWayland.so: /usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kscreen/KSC_KWayland.so
* KSC_QScreen.so: /usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kscreen/KSC_QScreen.so
* KSC_XRandR.so: /usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kscreen/KSC_XRandR.so
* KSC_XRandR11.so: /usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kscreen/KSC_XRandR11.so

> kscreen-doctor --outputs                                        
kscreen: Failed to request backend: unknown error
kscreen.doctor: Invalid config.

The file /usr/lib/x86_64-linux-gnu/qt5/plugins/kf5/kscreen/KSC_XRandR.so does exist.

Kubuntu 18.04.5

[jglen490]

Have you tried swapping cables, or connections on the PC side to rule out a possible bad cable?