This used to work... but I don't know why it's stopped working. Whenever I try to make a FaceTime audio call through my iPhone, I get "call failed". iPhone is on WiFi, same subnet as Mac (both on 192.168.2.0/24) subnet. Mac is on both WiFi (192.168.2.49) & wired (192.168.2.55) - both addresses DHCP assigned. No problems accessing devices on local intranet as well and other addresses on the good ol' world-wide-web. iPhone has a DHCP assigned address of 192.168.2.48. Router, DNS & subnet settings for both are the same. When my phone rings, I get the popup on my Mac. If I try to answer, I get "call failed". Update - it DOES work from my older MacBook Pro (again, same subnet, 192.168.2.47)... but that's not used much unless I'm traveling. OSX 10.11.6 iMac (Retina 5K, 27", Late 2014).