Head scratcher here. Have two instances of Rocky 8.6: one minimal install, one standard server w/ graphical. After running the system builds, xrdp was added. In the case of the minimal 8.6, gnome was added then xrdp. Short summary, we can connect to the 8.6 minimal with rdp but not the standard server. With the latter, we get non-descript error messages lead by “VNC error 1 after security negotiation.” Where to start??
My guess is that it has something to do with xorg, but I’m not sure. I did find a comment from this year (the very bottom of this link: 1575792 – xrdp closes session upon login) referring to comment 27 (above) that fixed this person’s issue. Your mileage may vary. I’m hoping that someone will comment here that has personally run into this issue and can better direct you!