I have coTurn and ejabberd set up on a Freedombox (Debian Pure Blend). I didn't create the configs myself. I entered some values into a config wizard when I said I wanted to install ejabberd, and the rest was done behind the scene.
Problem. I can complete calls to some users, but not to others. All have ejabberd accounts, and all are using Conversations IM app on Android. For those that don't work, the callee can see an incoming call, but after tapping the answer button, the call never gets completed. Voice and Video are the same.
I've tried called (and been called) without problem between my phone and a backup phone while my phone was on mobile data only, and the backup phone on wifi. I've successfully called (and been called by) my nephew who doesn't have and mobile data on his plan, so can only contect by Wifi. My nephew is in the same city. I can connect whether I'm using mobile data, or my wifi. However, I am unable to make or receive calls to a friend who lives several hundred kilometers from me.
I have server logs, and adb logcat output from Conversations IM. I'd be happy to share configs. Please let me know what information you need in order to help me figure out what needs fixing.
I should point out that I previously had the same problem with my nephew. It MAY have been (emphasis intentional) because I added a "listening-ip" directive with my ipv4 static address to the 2 existing "listening-ip"directives that were in ipv6 format only. But, kids being sometimes hard to pin down to do testing with, I haven't conclusively determined that it was my config change was responsible and not my having restarted the server.
If anyone can think what may be missing in my coturn setup, please let me know