Hi, I have a potential customer who currently have Gamma SIP trunks. I have set up 3cx to test this as a proof of concept for them but I am receiving a 403 forbidden message back from Gamma when trying to make outbound calls. Gamma have done a trace of the call and they are seeing the internal IP address in the contact header. Does anyone know if there is something I can specify in the outbound parameters to make that display the external IP address? Initially i thought this might be a NAT issue but there are NAT rules in place. Has anyone else used Gamma via 3cx?