Speech path being blocked after call established

Qball

Afternoon all, I'm having a strange problem with a softphone app running through PFsense. I can get the app to register fine and then also make and connect the call. Straight after the call you can hear the voice path drop. There is a voice path there only for around 2 - 5 seconds. The call still stays established but no speech path either way. Has anyone seen this before? A standard desktop Phone works okay via NAT etc.
Seems to be something blocking the RTP stream after the set-up

JKnott

@qball

Since you're behind NAT, you need to use an STUN server to tell the other end what your real address is. There may also be some issues with maintaining the path through NAT for UDP.