Both my girlfriend and my immediate family members are people I use iMessage with, daily. Today, my girlfriend's iphone4S stopped receiving iMessages. Neither of us can send imessages to each other. We restarted the messages app, restarted phone, jiggled off/on wifi, turned "send as sms" OFF, yet no avail - our texts are still sending as SMS today instead of imessages like the past couple months. I can still facetime with her. Neither her email nor her phone number gets imessages, just green SMS texts. What am I doing wrong?