Bizarre Android problems with high-performance backend

Hi everybody,

I am running Nextcloud for some years now, and reserved some quiet January time for scrutinizing the Talk setup and installing the by now open-sourced signaling backend.

I basically followed [1] up until the webserver setup which I did according to [2]. In the admin’s Talk settings, the high-performance backend is successfully recognized. The first minor issue is that the TURN server gets not recognized correctly if I enter the domain name. (Message: No ICE candidates found.) It does however work if I enter the bare IP address - which is a bit unfortunate if I want to set up virtual hosts because then I can not distinguish according to subdomain. So maybe somebody has a simple solution in mind - I already tried for hours and hours.

The main problem is the following: While I can connect successfully with 5 different desktop PCs via Firefox and Chrome, the whole call starts to break (even for some of the desktop users) when an Android client dials in. Here it doesn’t matter if the mobile device is connected via LTE or via Wi-Fi. Using the browser on the mobile seems to work at least somehow, but not all video streams are switched on, I guess that is due to some limitations of the mobile web browsers (tried Firefox and Chrome).

Does this ring somebody’s bell? Any ideas? Thanks so much! Actually I was under the assumption I had it working once, but it was late at night and I might be misled. I was thinking it might be some certificate issue with Android, but I wouldn’t know which. The Nextcloud server has a well-working letsencrypt certificate (the main Nextxloud app works without problems), and the backend has a well-working letsencrypt certificate.

Nginx proxies internally to signaling on port 8086, but I guess without SSL, so I have no handle as to where the problem could be.

Now for 1 on 1 calls, the situation is the following: If I set up a session just with one desktop and one Android device, then I can get it to work on two different Android devices if I use Wi-Fi on both of them. If I turn off Wi-Fi and use LTE instead on both of them, only one of the devices (the much older one) works. Restarting the devices did not help. Confusing!

My hope is that all these things make sense to the experienced people in this forum.

Kind regards

[1] Nextcloud Talk mit coturn und eigenem Signaling-Server (High Performance Backend) | Arno Welzel
[2] Nextcloud Talk mit eigenem Signaling-Server (High Performance Backend) » DecaTec

Hi there! Does anybody have an idea about this problem? In short, joining via app does not work reliably on Android, while it does work well on desktop.

Kind regards

No ideas at all?