Ever since I unintentionally upgraded to two-factor verification from two-step verification, I can no longer sign-in to my account on my Apple TV (1st gen). All other devices work except the Apple TV.
Apple TV
See the following from Two-factor authentication for Apple ID - Apple Support
What if I use two-factor authentication on a device running older software?
If you use two-factor authentication with devices running older OS versions—like an Apple TV (2nd or 3rd generation)—you might be asked to add your six-digit verification code to the end of your password when signing in. Get your verification code from a trusted device running iOS 9 and later or OS X El Capitan and later, or have it sent to your trusted phone number. Then type your password followed by the six-digit verification code directly into the password field.
See the following from Two-factor authentication for Apple ID - Apple Support
What if I use two-factor authentication on a device running older software?
If you use two-factor authentication with devices running older OS versions—like an Apple TV (2nd or 3rd generation)—you might be asked to add your six-digit verification code to the end of your password when signing in. Get your verification code from a trusted device running iOS 9 and later or OS X El Capitan and later, or have it sent to your trusted phone number. Then type your password followed by the six-digit verification code directly into the password field.
If you really have the 1st generation model from 2007, then that is technically and functionally obsolete now. It will not connect online anymore. You can watch or listen to non-DRM content that’s still on the disk, and that’s about it.
Identify your Apple TV model - Apple Support
If your Apple TV box is black, then it is at least 2nd generation.
The reply marked Helpful in the following previous discussion may also help: Apple TV 1st generation two factor authen… - Apple Community
Apple TV (Gen 1) sign-in after upgrading to two-factor verification on other devices.
