I just rented a movie on my iPhone, with the intention of watching it on my Apple TV . How ever when I go to the place where it says "check for rentals" it won't find it. I have tried signing out and back in, it did not work. What should I do?
Welcome to the Apple Community Vane_paranormal.
If you rent a movie on your phone, you have to watch it on your phone, likewise if you rent it from the Apple TV you will have to watch it there.
If you want to watch a rental on multiple devices, rent it from a computer.