xrdp has been working fine with XUBUNTU 16.04 but on a fresh install of XUBUNTU 18.04, my attempts to remote log-in always result in failure. A small portion of the xrdp.log is:
xrdp_wm_log_msg: login successful for display 10
xrdp_wm_log_msg: VNC started connecting
xrdp_wm_log_msg: VNC connecting to 127.0.0.1 5910
VNC error 1 after security negotiation
VNC error before sending share flag
VNC error before receiving server init
VNC error before receiving pixel format
VNC error before receiving name length
I have the firewall down while trying this issue.
Since moving my test system to Ubuntu 20.04, I have found there is a change in XRDP or something related. Through Ubuntu 16, it was possible for multiple systems to be logged into the same Ubuntu user ID at the same time. That appears no longer to work. Even if you think you no one else is logged in - remember, the console of the system itself is a GUI session and is logged in on that ID. I am able to get around the problem by logging off the GUI session of the console. This work-around was discovered when I had success using xrdp on any ID except the primary ID of the new Ubunto 20.04 system.