Apple Tv+

If you do not have the TV icon on your Apple TV then make sure it's up to date (firmware 7.5). If the issue is with signing in, then as stated it would have to do with 2 factor authentication. As you have an older model Apple TV you would need to enter the password and code together, however to avoid the time limit you will need to just enter the password, then manually request the code and add it to the password

Get a verification code and sign in with two-factor authentication - Apple Support

No.

Well you either did not pay for it, redeem a free offer of complete 2 factor authentication. Those are the likely suspects, however without more info from you that’s about all I can think of.