You probably already done this, but have you made sure that you configured static nat port mapping on pfsense, as recommended by them for a VoIP server behind pfsense using nat?
https://docs.netgate.com/pfsense/en/latest/recipes/nat-voip-pbx.html
You probably already done this, but have you made sure that you configured static nat port mapping on pfsense, as recommended by them for a VoIP server behind pfsense using nat?
https://docs.netgate.com/pfsense/en/latest/recipes/nat-voip-pbx.html