The Apple TV 1st Generation (released in 2007) predates the modern App Store ecosystem for TV.
You on an Apple TV 1st Generation . Unlike newer models, this original device does not have an App Store. It was designed primarily as a hard-drive-based media player for syncing content from iTunes on a computer. Why You Can’t Download Apps how to download apps on apple tv 1st generation
It runs a modified version of Mac OS X rather than the modern tvOS . The Apple TV 1st Generation (released in 2007)
Apple discontinued support for this model years ago. It can no longer connect to the iTunes Store for streaming or rentals due to outdated security standards. How to Get Content on the 1st Gen It was designed primarily as a hard-drive-based media
The App Store was only introduced with the 4th Generation Apple TV (Apple TV HD) in 2015.