iPad Mini to Mac Facetime. So confused.

So, my wife has a Macbook, and I have an iPad mini. We both share a an Apple ID. Whenever one tries to FaceTime the other, it comes up as unavailable. I already changed the email on the mini, but not the ID, as it says in another post, but that didn't work at all. No matter what I do, it will not connect. I am thinking perhaps someone else may know the answer, before I accidentally throw this thing through the wall in frustration, lol. Please help!