A variety of glitches and setting issues can cause Netflix to disappear from your Apple TV. The problem may be due to Netflix's servers, the Apple TV device or even your Internet connection. Fixing the problem may require trying a few processes, and you will most likely need to re-enter your Netflix account information again once the option is restored.
Netflix Server Issues
Every once in a while, Netflix may have trouble with the servers that host its content. This occurrence is rare, and Netflix takes measures to minimize the possibility, such as server failure simulations and automated reactions to such failures. Visit the Netflix website on your computer or mobile device and attempt to stream a movie to see if the service is functioning. If it is, then this is not the problem with your Apple TV. If the Netflix website won't allow you to stream, the problem is on its end and you will need to wait until service is restored.
Apple TV Issues
Former Apple CEO Steve Jobs referred to the Apple TV device as a "Hobby" for Apple. It is still a bit of a work in progress, and sometimes it has glitches. If Netflix is not appearing on your Apple TV, use the on-screen menu to check for updates to the device's software. Install any available updates and return to the home screen to see if Netflix reappears. If not, try unplugging the Apple TV from its power source for 30 seconds, then plug it back in to reboot it. You can also reboot the device by holding down the "Menu" and down arrow buttons on the remote until the light on the Apple TV device blinks rapidly.
If your Apple TV lacks a network connection, you may not see any of the Internet services listed. Check your modem and wireless router to see if they are working properly. If not, contact your service provider for assistance. If they are, go to "Settings" on the Apple TV, and check your network connection. You may need to re-enter your network name and password. Restart the Apple TV before you re-connect to the network in case other system glitches caused this error.
Glitches between Apple TV and Netflix are more common than glitches with the iTunes connection. This is because Apple created and manages iTunes, and specifically designed the Apple TV to work with it. Netflix manages its own software, so any changes they make to their content delivery system can affect how it works with Apple TV until the Apple TV software receives a corresponding update.