My Apple TV does work on Netflix

Has it worked before? If not, then a router setting might block some network functionality for Netflix specifically.

Does Netflix work on your phone or computer, using your home network?

Netflix will block VPN users that they can detect, if you use that. Not sure what kind of error they get.

Set Apple TV to use the Auto IP and Auto DNS, to have the router supply network settings.

An often cited general Netflix troubleshooting step is:

1. sign out of your Netflix account
2. unplug Apple TV for 1 min.
3. start Apple TV again
4. sign in to your Netflix account

Glad to hear it works on Netflix and YouTube. But where do you see the code, and what did you do when it came on?