The following is our setup... We have two locations and the 3cx system is located at site 2. We have a vpn connection between site 1 and site 2. The vpn is created using our firewall appliance which exists at both locations. Site 2 which has the 3cx phone system can place calls without any issue to site 1 or the outside. Site 1 can call site 2 using a softphone and no issues with sound. If site 1 tries to place a call to the outside though the 3cx box then the call rings but once the party picks up there is no sound. If I setup a softphone at my house and place a call to an extension or another outside number there is no sound and even if I pick up after a few seconds it drops the call and says "ACK is not recieved". I know this worked before... And if it works between both sites could it be the firewall at site 2?