Black screen in xrdp

I have a pretty generic Kubuntu install and cannot RDP into it. I installed xrdp and created the .xsession file and can connect successfully from my Mac. I get the KDE logo with the spinning gear, and then the screen goes black with an "X" cursor that I can move around the empty screen. That's it. I am using stock SDDM as a display manager. If I switch to lightdm, xrdp works great, but I can't log into the machine the regular way so that's a fail. I need to stick with SDDM to use my machine normally. Can someone help?