I installed Ubuntu 20.04 and then installed xrdp. Whenever i tried to connect, either from another Ubuntu 20.04 box using either xfreerdp or krdc, or from a Mac, a black screen would show up, and then immediately disconnect. i made sure i did not have any other sessions on the server going on at the same time.
After a while, i gave up and tried the script at: https://www.c-nergy.be/products.html it didn't make a difference
this is the only output from /var/log/xrdp.log
[20200529-18:17:16] [INFO ] Socket 12: AF_INET6 connection received from ::ffff:192.168.0.216 port 45006
[20200529-18:17:16] [DEBUG] Closed socket 12 (AF_INET6 ::ffff:192.168.0.199 port 3389)
[20200529-18:17:16] [DEBUG] Closed socket 11 (AF_INET6 :: port 3389)
[20200529-18:17:16] [INFO ] Using default X.509 certificate: /etc/xrdp/cert.pem
[20200529-18:17:16] [INFO ] Using default X.509 key file: /etc/xrdp/key.pem
[20200529-18:17:16] [DEBUG] TLSv1.3 enabled
[20200529-18:17:16] [DEBUG] TLSv1.2 enabled
[20200529-18:17:16] [DEBUG] Security layer: requested 3, selected 1
[20200529-18:17:16] [INFO ] connected client computer name: coruscant
[20200529-18:17:16] [INFO ] adding channel item name cliprdr chan_id 1004 flags 0xc0a00000
[20200529-18:17:16] [INFO ] TLS connection established from ::ffff:192.168.0.216 port 45006: TLSv1.3 with cipher TLS_AES_256_GCM_SHA384
[20200529-18:17:16] [DEBUG] xrdp_00000506_wm_login_mode_event_00000001
[20200529-18:17:16] [INFO ] Loading keymap file /etc/xrdp/km-00000409.ini
[20200529-18:17:16] [WARN ] local keymap file for 0x00000409 found and doesn't match built in keymap, using local keymap file
[20200529-18:17:17] [DEBUG] Closed socket 12 (AF_INET6 ::ffff:192.168.0.199 port 3389)
[20200529-18:17:17] [DEBUG] xrdp_mm_module_cleanup
thank you very much