Comment # 14 on bug 1203468 from Stefan Willer

The most recent xrdp uses a vanilla upstream config in /etc/pam.d/xrdp-sesman,
which does not include /etc/pam.d/common*. If you rely on a special method of
authentication configured via pam-config in those files (like sss), it won���������t
work with xrdp. Here���������s a quickfix for that scenario:

cd /etc/pam.d && cp samba xrdp-sesman

The samba file is just a very basic config that has all the necessary includes.
I do not know if it is optimal for xrdp.

This should probably be changed when packaging xrdp for Tumbleweed.