Multiple monitors with xfreerdp and Xvfb

I am trying to start an X server with multiple screens on a single Xvfb like this: Xvfb :50 -screen 0 1792x1120x24 -screen 1 1792x1120x24 and start an RDP connection which will use those two screens: DISPLAY=:50; xfreerdp /w:1792 /h:1120 /monitors:0,1 /multimon /u:... /p... /v:... This doesn't work like this, the xfreerdp process crashes. I've tried some combinations of /span and monitor numbers and /multimon:force and nothing worked. When I'm trying the same with one monitor and one Xvfb screen it works. I also don't understand how do I set resolutions per screen/monitor in xfreerdp since I have just one of each /w and /h. Also tried to xfreerdp /monitor-list after starting Xvfb with one or two screens. After starting Xvfb with one screen, the monitor-list printed it correctly. But with two xvfb screens, the monitor-list printed nothing. Thanks for any answers or even hints!