Comment # 1 on bug 1138954 from Felix Zhang

Looks also reported on Debian:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=840132#20f

Michael, could you please try editing
/usr/lib/systemd/system/xrdp-sesman.service like:

-After=network.target
+After=network-online.target
+Wants=network-online.target