The facetime on my new (of three days) Macbook Pro isn't working anymore. I've only used facetime to call about two times and now it isn't working. Whenever I try to call, it either rings and then says "FaceTime failed" or says that right away. I then asked my friend that I tried to facetime if she ever got a call, but she said no.. I know I'm calling with the right number.. Whats wrong?