I'm using iPhone 6 plus/8.1.2 and MBA 2014/10.10.1. At home, I can answer/call from my Mac, works fine, no problems here. Both devices connect to the same WiFi router. In my office, I notice that when I get a call, I'd hear it on my iPhone, and see it on my Mac. However, answering on the Mac would get an error. I suspect the cause is that I have two network connection on the Mac, combination of WiFi and Thunderbolt/Gigabit, each connection has its own public IP addresses. The iPhone is connected to this same Apple Airport Express as the Mac, so it shares the same WiFi network. Anyone has this similar set up? Yes I could unplug the Thunderbolt/Gigabit adapter, it's nicer to have it for file transfer.