Finally was able to install v15 and work around external connectivity to the pbx. However, there is no audio when I call from an external device such as an iphone. I'v configured the ports in the firewall as indicated. When I run the firewall checker I still get errors in some ports. I've tried to reach 3cx support but configuration outside of the pbx (such as in my server) is not allowed. Any ideas as to what might be wrong?