Weird behavior of Nextcloud Talk in LAN


I have latest Nextcloud Docker version (Apache) (18.0.4) behind nginx reverse proxy, and we have several issues with Nextcloud Talk. Firstly, I will describe my network structure: => there is Nextcloud (IP .1.5) and computers (IP .1.20 and .1.23) => there are mobile devices (IP .0.6, .0.9 and .0.13)

Everything is in LAN, nothing should be in WAN, default STUN and no TURN server.

We tried various combinations:

  • browser with browser (.1.20 and 1.23) => works good
  • android with android (.0.6 and .0.9) => works good
  • android with iPhone (.0.6 and .0.13) => not working
  • browser with android (.1.20 and .0.6) => Android sees browser screenshare, but browser can’t see android’s webcam share

I’m quite not sure how I can diagnostic this issue, can be this firewall issue? What ports does it need for working? Can TURN server helps?