facetime shows connecting whilst still ringing but never connects

I recently upgraded my macbook air from mavericks to yosemite and whilst trying to use facetime to call another laptop running OS X Lion it keeps showing connecting whislt still ringing in the background but doesn't connect.

If I use my macbook running OS Leapord I can connect easily no problems.

Tried turning facetime on and off, restarting macbook air, turning handoff off, not signed into icloud but nothing helps..

any solution for a fix will be greatly appreciated