Veyon Service works only when run manually from X Windows session

[AlexDesyatnik]

Hi, I've run into this problem. Journalctl logs show the following:

июл 31 13:29:59 localhost.localdomain systemd[1]: Started veyon.service - Veyon Service.
июл 31 13:29:59 localhost.localdomain veyon-service[10174]: No protocol specified
июл 31 13:29:59 localhost.localdomain veyon-server[10174]: qt.qpa.xcb: could not connect to display :1
июл 31 13:29:59 localhost.localdomain veyon-server[10174]: qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
июл 31 13:29:59 localhost.localdomain veyon-server[10174]: This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
                                                              
                                                              Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.

Systemctl shows that service is working, but it doesn't accept incoming connections when tested with telnet IPADDR 11100. When I start veyon-service manually from X Windows session (MATE if that matters), all works just fine so it isn't misconfigured firewall. Disabling X Damage in Veyon Configurator changes nothing.