I can't get movies to stream from my iTunes account to my AppleTV even though home sharing is on on both devices
I can't stream movies from my iTunes account on my iMac to my AppleTV even though home sharing is activated on both devices
Apple TV
Are you using the same Apple ID on ATV and iMac?
Is all software up to date?
What version is your ATV?
Have you checked the items here Get help with Home Sharing - Apple Support ?
What do you see in the ATV Computers app?