This is an old bug. I also found it. It is not a network issue. I installed gpsd but it still not working.
file:///usr/share/kpackage/kcms/kcm_nightcolor/contents/ui/main.qml:344: TypeError: Cannot read property 'latitude' of undefined
file:///usr/share/kpackage/kcms/kcm_nightcolor/contents/ui/main.qml:345: TypeError: Cannot read property 'longitude' of undefined
org.kde.plasma.dataengine.geolocation: gpsd not found