Q: My movie won't download on my iPad. It says Unable to Download. Try again or Done. I'm on my FiOS home wifi and there's an excellent download speed. Can you help me?

Not sure if this helps but I took a layman's approach; signed out of iTunes, then tapped the cloud with arrow icon a number of times in quick succession which prompted a re-enter the password and ID screen. Now downloaded fine. Maybe coincidence but it worked.

I've encountered the same problem. Unfortunately, the only thing that Apple Support told me to do was to download the movie onto my macbook and then manually sync it onto my iPad. That's very frustrating for me as it doesn't solve the problem of why it won't load directly to my iPad, even if I try different networks. It seems to me that there should be more consistency where if the movie is 99% downloaded and then crashes you don't have to start downloading again from 0%.