After giving admin permissions to a user, xrdp shows a black screen

My host is an Ubuntu 22.04.1 machine on Oracle server, my client is an Ubuntu 20.04.5. The connection was established via xrdp 0.9.17 using Xorg with no issue. Following this guide, I tried to give admin permissions to the single user I have on my host. In particular, I set a password for that user and created the file

/etc/polkit-1/localauthority/50-local.d/46-user-admin.pkla 

with the following content:

[Authorize admin control of user settings]
Identity=unix-user:*
Action=org.freedesktop.accounts.*;org.gnome.controlcenter.user-accounts.*
ResultActive=yes
ResultInactive=yes
ResultAny=yes 

and rebooted. After this and a successful log in with xrdp, I get a black screen. Trying to log in with a wrong user or a misspelled password, I get an error as expected, but with the right credentials there is a plain black screen. SSH connection is working just fine.

I tried to remove completely xrdp (usual purge and manual erase of few folders), reinstall it, reconfiguring it (changing port protocol to tcp). At first the status of the xrdp service is OK, but after a failed login attempt I get:

me@me:~$ sudo service xrdp status
xrdp.service - xrdp daemon
     Loaded: loaded (/lib/systemd/system/xrdp.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2022-11-10 09:35:06 UTC; 2min 9s ago
       Docs: man:xrdp(8)
             man:xrdp.ini(5)
    Process: 2578 ExecStartPre=/bin/sh /usr/share/xrdp/socksetup (code=exited, status=0/SUCCESS)
    Process: 2586 ExecStart=/usr/sbin/xrdp $XRDP_OPTIONS (code=exited, status=0/SUCCESS)
   Main PID: 2587 (xrdp)
      Tasks: 1 (limit: 28694)
     Memory: 812.0K
        CPU: 42ms
     CGroup: /system.slice/xrdp.service
             └─2587 /usr/sbin/xrdp

Nov 14 09:36:26 me xrdp[2654]: [INFO ] xrdp_process_offscreen_bmpcache: support level 1 cache size 7864320 MB cache entries 2000
Nov 14 09:36:26 me xrdp[2654]: [WARN ] Client Capability: not enough orders supported by client, client wants off screen bitmap but offscreen bitmaps disabled
Nov 14 09:36:26 me xrdp[2654]: [INFO ] Loading keymap file /etc/xrdp/km-00000407.ini
Nov 14 09:36:26 me xrdp[2654]: [WARN ] local keymap file for 0x00000407 found and doesn't match built in keymap, using local keymap file
Nov 14 09:36:26 me xrdp[2654]: [INFO ] connecting to sesman ip x.x.x.x port 3350
Nov 14 09:36:26 me xrdp[2654]: [INFO ] xrdp_wm_log_msg: sesman connect ok
Nov 14 09:36:26 me xrdp[2654]: [INFO ] sesman connect ok
Nov 14 09:36:26 me xrdp[2654]: [INFO ] sending login info to session manager, please wait...
Nov 14 09:36:26 me xrdp[2654]: [ERROR] xrdp_iso_send: trans_write_copy_s failed
Nov 14 09:36:26 me xrdp[2654]: [ERROR] Sending [ITU T.125] DisconnectProviderUltimatum failed

and looking at the Xorg sessions, there are so many entries:

me@me:~$ xauth list
me/unix:11  MIT-MAGIC-COOKIE-1  xxx
me/unix:10  MIT-MAGIC-COOKIE-1  yyy
me/unix:12  MIT-MAGIC-COOKIE-1  zzz
me/unix:13  MIT-MAGIC-COOKIE-1  www
me/unix:14  MIT-MAGIC-COOKIE-1  uuu

I tried to dig a bit more for the error trans_write_copy_s failed, but I think there is something wrong with my user.

I would appreciate any input from you. Thank you.