Episode not downloaded to Apple TV

I have purchased the full series of Castle season 5, and every time a new episode is available I get an email notification and it gets downloaded automatically in my Apple TV (1st Gen). However, for episode 18, I got the email notification, but the episode was not downloaded into my Apple TV. I checked for downloads, and I also tried signing out and in again, but still did not get the episode! Can someone help please? Thx