I' miss having the same issue. If you go into setting and test your network speed, it asks for the code. That's the only place I've found to input it so far. IT WORKED!!!

If you are using two-factor authentication on an older device…You should be able to append the code to your password and enter that (i.e. if your password is ABC and your code is 123, enter ABC123), however if this doesn't work it may be that you are running out of time using your authentication code and you may want to delay getting your code until the last minute or temporarily disable the 2 step verification/2 factor authentication, although it shouldn’t be necessary.Get a verification code and sign in with two-factor authenticationThe following was posted by another user…From an iPhone or iPad, go into "Settings" => click on the top bar with your name and "Apple ID, iCloud, iTunes & App Store".While still on iPhone or iPad, tap on "Password & Security", then tap on "Get Verification Code", LEAVE the supplied verification code visible.Go to the iTunes login on your AppleTV settings and start logging in.When it asks for your password, enter your password and add the verification code to the end of your password BUT DO NOT HIT SUBMIT YET !!!Go back to your iPhone/iPad and tap on "OK" on the verification code to make it go away.Now go back to your AppleTV and submit the password.

Which Apple TV device? If it's a first gen you can not login. With a 2nd or 3rd gen you may be able to using this process: If you have an Apple TV (2nd or 3rd generation) and two-factor authentication for your Apple ID, then you may be asked to type your password followed by the six-digit verification code directly into the password field. Additionally, there is a time limit , after which the code becomes invalid. Try this: First enter the characters of your password (do not submit yet), then manually request a new verification code , then append that code to the password (no spaces or other separating characters), and then submit. That should help you get passed the time limit. All three of those generations have obsolete status and are no longer supported they are all over ten years old.