Have you had issues with your Netflix App on the 4th Generation Apple TV? Is it constantly freezing, hesitating, buffering, or loading while trying to play a title? Have you tried all of these solutions to no avail? (Netflix Knowledge Base)
1. Restart your Apple TV
Unplug your Apple TV and the TV it's connected to for at least 2 minutes.
Plug both devices back in.
Turn both devices back on.
Try Netflix again.
2. Reinstall the Netflix App
From the Apple TV home screen, highlight the Netflix app.
Press and hold in the center of the touchpad until the Netflix icon starts to shake.
Press the play/pause button to delete the app
Select Delete again to confirm
Reinstall Netflix from the App Store and try Netflix again
3. Update Apple TV Software
If your Apple TV isn't up to date with the most current software updates, it can cause streaming issues. To check for updates on your Apple TV:
From the Apple TV home screen, select Settings.
Select System.
Select Software Updates.
Select Update Software. If your firmware is out of date, you will see the option to Download and Install. Select it to upgrade your Apple TV firmware. Once you've downloaded any available updates (or if there were no updates available), try Netflix again.
If these do not work, there is another, simple solution that may resolve this issue.
Are you connected to the internet via ethernet or wifi? If you answered ethernet, then this maybe your culprit. Users are reporting that there is a speed/duplex issue with the ethernet port on the Apple TV 4. While your Speedtest may yield 80mbps download rates, Netflix on the Apple TV is particularly vulnerable to the issue.
Solution:
Switch to Wifi. To do this, simply unplug your ethernet cable and go to Settings > Network. On Apple TV (2nd or 3rd generation), go to Settings > General > Network. Choose the name of a compatible Wi-Fi network to join. If asked, enter your Wi-Fi password. (Apple Wifi Help)
This fixed the issue for us. We dealt with this issue for 2 months, while Netflix worked perfectly on all devices with the exception of the Apple TV. Since I have switched to Wifi, I have had no issues.