The facetime on my Macbook Pro isn't working

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?