New accounts created on smart TVs and third party streaming devices may need to be activated through the Apple website activate.apple.com. During the account creating procedure, you would get a code displayed on screen, to be copied to the website. Did you get a code on the TV screen?
How to create a new Apple ID - Apple Support
New Apple ID accounts need full user details as asked, a verified email address (respond to test message), and a valid payment method.
Signing in on a new device with a pre-existing account may require a verification code as part of two-factor authentication. This helps avoid fraudulent use, as the account holder will be notified when this new sign-in happens. This is a different code that the activation code mentioned above. The verification code will be send to you trusted Apple devices or trusted phone number(s), as identified for your account.
Two-factor authentication for Apple ID - Apple Support
Get a verification code and sign in with two-factor authentication - Apple Support
If the network connection isn’t blocking communication, then you should be able to sign in as intended.
If the issue persists, then I would suggest to contact an expert from the Apple Support staff for further assistance. Contact Apple for support and service (phone numbers) or start your support request online (chat/email/callback).