Facetime not working

I just got an iPhone 7 Plus today and I tried calling a friend and the call went through but as soon as they tried to answer it said facetime unavailable. They tried calling me and it did the same thing. It worked perfectly fine on my iphone 6 but not this one. Facetime audio works but as soon as you try to switch to facetime video, it says facetime unavailable. I've already tried everything listed in the support tabs already.