This problem seems to have been occurring for years to judge by the number of results I got when I googled it, but I've yet to read a definitive solution to the problem. My iPhone 4S on iOS 8.6 worked just fine with my Mac on Yosemite - I could call from my Mac using the iPhone connected over wi-fi. Since updating to iOS 9.2.1 I can no longer use Facetime and receive the message "your iphone is not configured to allow calls using your mac". There doesn't seem to be any way of correcting this: I'm logged in with the correct password and User ID and as far as I can tell all settings are correct. I've tried restarting my phone, switching Facetime off, etc but to no avail.
Strangely, iMessage seems to be working fine.
If it is such a common problem, where is the common solution?
