Da es einige Probleme gab, den XRDP Server unter Ubuntu 18.04 LTS zum laufen zu bringen, habe ich hier die Lösung dokumentiert, die mir letztlich weitergeholfen hat.

Quelle: https://c-nergy.be/blog/?p=11868

Install xRDP Software

sudo add-apt-repository ppa:martinx/xrdp-hwe-18.04
sudo apt update
sudo apt install xrdp
sudo adduser xrdp ssl-cert
sudo reboot

Install Gnome Tweak Tool

sudo apt install gnome-tweak-tool

Allow console Access and create policies exceptions

sudo sed -i 's/allowed_users=console/allowed_users=anybody/' /etc/X11/Xwrapper.config

sudo bash -c "cat >/etc/polkit-1/localauthority/50-local.d/45-allow.colord.pkla" <<EOF
[Allow Colord all Users]
Identity=unix-user:*
Action=org.freedesktop.color-manager.create-device;org.freedesktop.color-manager.create-profile;org.freedesktop.color-manager.delete-device;org.freedesktop.color-manager.delete-profile;org.freedesktop.color-manager.modify-device;org.freedesktop.color-manager.modify-profile
ResultAny=no
ResultInactive=no
ResultActive=yes
EOF

Enable Extensions

gnome-shell-extension-tool -e ubuntu-dock@ubuntu.com
gnome-shell-extension-tool -e ubuntu-appindicators@ubuntu.com