I have a similar problem. I installed jitsi on Ubuntu on a vm running on qemu/kvm. When we log in via our no-ip dynamic dns host name from inside our home network, everything works great.
However, when one participant is coming from outside we get exactly what is depicted in the OP’s screenshot. People inside the network can see each other but those on the outside network cannot participate. Everyone sees their own mic/camera as active and the mic/camera of those on the other network as muted.
Text chat however functions for everybody regardless of where they are.
I have not enabled port 5349 nor mapped it on the router as I am not really sure if it is essential. Is 5349 essential, could this be a symptom? If not, which log files should I be looking at?
I am a total newbie to this. First time I have ever tried to install a comms program of any kind.