When speaking to support the other day the tech told me to run ip maddr show which I did and he said that my multicast port was wrong since it was not 184.108.40.206 He said there was an issue with Pi3 I believe and I needed to disable Wifi. I added line dtoverlay=pi3-disable-wifi in config.txt and then SBC Worked and showed this IP address. Now I am setting up a new Pi SBC and have similar situation . I did the same steps as previously but still not seeing that IP address and pbx is still not communicating with SBC. Anyone have a suggestion? Thanks.