by bridonca » 12/11/2014
It seems that you have NAT issues with the router, and there is no easy solution. If you are using wifi, you can configure the router to forward certain ports to the phone, but the router might just not be capable of forwarding packets properly. You might need a new router, and if you do decide to get one, make sure it is capable of being flashed with DD-WRT.
If you are trying to do this through cell data, again, it is a NAT issue, but with the ISP, so you cannot replace that.
You might be able to get the audio routed correctly if you configure for a STUN server. STUN can tell what type of NAT is running, but it is not very useful in fixing the NAT problem.
The nuclear option is to set up a OpenVPN tunnel. You need a reliable OpenVPN server on the other end because you will be using it's NAT and IP. But at least it should be better than the NAT from your telco,