Having problems getting my face time to work properly. Keeps telling me that it can not verify my email address? Any ideas?

Have multiple apple products, iPhone, iPad, and Mac computer. I was trying to face time on the Mac and it continues to tell me that it cannot verify my address. The only thing that I can figure out is that the e-mail and apple id that I use is shared between products, how can I fix and use the computer to face time?