If you received this device from a previous owner, then you are advised to first reset to factory settings, and then set it up again “as new”. Reset or restore your Apple TV to its factory settings - Apple Support. After a reset, any previous account information and other customization will be erased.
Verify that the system software is up-to-date: Update your Apple TV - Apple Support. We’re on tvOS 17.3 now.
Users should find the current sign-in in: Settings﹥User and Account﹥… The default user would often be the primary user. Enter your Apple ID account and password there. If a different account was listed, then you may need to first sign out for that other account, or else add a secondary account, depending on your household.
Apps stay linked to the user account as was active when installing that app. The account credentials will be needed for app updates, as the App Store wants authentication. To break a link with an old account, delete and reinstall that app, to link it to the current account.
If you have two-factor authentication for your Apple ID [3], then you may be asked to enter the verification code [4], as received on one of your trusted Apple devices or else on a trusted phone number.
