apple tv 4 k settings says check network connections

Is your Apple TV internet-connected via ethernet or Wi-Fi? You’ll need one of these.

Is this used in a home setting, where a home network is present?

Have you tried restarting your router (and optional other network gear)?

Have you tried restarting your Apple TV box?

Is this for a newly set up Apple TV box, or did it work before?

If your Apple TV can't connect to Wi-Fi - Apple Support

Recommended settings for Wi-Fi routers and access points - Apple Support

Resolve Wi-Fi and Bluetooth issues caused by wireless interference - Apple Support