"my apple tv does not let me sign in with a verification code it keeps going back to start the process again" – Answer

The fix to the problem that older generation Apple TV's won't let you sign-in:

On your Apple TV:

Go to Settings -> iTunes Store -> Sign-in

Enter your username and password as usual but BEFORE submitting:

On your primary device (iPhone, iPad, Mac, etc.):

Settings -> Click your name at the very top to access Apple ID info -> Click Password & Security -> Click "Get Verification Code" towards the bottom -> Enter this code (without spaces) at the end of your password, THEN submit.

This worked on my Apple TV (3rd Generation) Model: A1469 - thanks to Apple Support