I have recently got an XZ1, at first all was working fine then recently it just stopped ringing. It wasnt in DND mode. Each call attempt would cause two vibrations and then the call woulkd drop, the onscreen notification at the top was not appearing.
I was just about to re-install the OS as all settings suggestions found here failed. Before doing this I tried unistalled the last App I installed, a Compass app. After doing this the ringing popup at the top of the screen appeared on a call, but still no ring tone. I then swithched the ringtone to a standard Xperia one, and then it started ringinging again.
My daughter had a Z3 and that frequently never rung. I think there must a bug in the Phone App somewhere as I have seen many similar posts. Other than this the phone is awesome.
