DIAGNOSIS: The integrated Wi-Fi module in these TVs can have trouble maintaining a stable connection, especially on crowded 2.4GHz networks or if your router uses certain power-saving features for connected devices.
FIX: First, try assigning a static IP address to your TV within your router's settings. This prevents DHCP lease timeouts from dropping the connection. If that's too technical, try switching the TV to a 5GHz Wi-Fi network if your router supports it (the TV does). The 5GHz band is usually less congested. You can also try a full network reset on the TV: Settings > Network & Internet > Forget your network, then reboot the TV and reconnect.
IF THAT DIDN'T WORK: The most reliable fix is to bypass the Wi-Fi entirely. Use a wired Ethernet connection if possible. If the TV is too far from your router, consider a powerline Ethernet adapter kit, which uses your home's electrical wiring to extend a stable wired connection.
HEADS UP: If you go the Ethernet route, the TV's port is only 10/100 Mbps, not Gigabit. That's still plenty for 4K streaming, but don't expect super-high speeds for large file transfers from a local server.