_IceTransSocketUNIXConnect: Cannot connect to non-local host

So I’ve got a lxc container (centos 7) that needs to run a particular closed source commercial graphical app. (That app requires this old centos7 distribution, there is nothing I/we can do about it. I’ve wasted a lot of time already trying to run it on sth. newer…)

That app brings it’s own version of several libs like libQt5…, libxcb… and so on…

Now I get the warning

_IceTransSocketUNIXConnect: Cannot connect to non-local host

when launching that app.

What does it mean? Can I get rid of if?

Host system is wayland based, Xwayland is working.

I’ve mounted /tmp/.X11 inside the container.

xeyes runs smoothly inside container

xterm runs smoothly inside container, but throws warning

_IceTransSocketUNIXConnect: Cannot connect to non-local host container-host
_IceTransSocketUNIXConnect: Cannot connect to non-local host container-host
Warning: Tried to connect to session manager, Could not open network socket

I’d like to understand what is happening here.