DIAGNOSIS The TV's Wi-Fi adapter is losing its connection, often due to interference or a weak signal.
FIX Forget the network and reconnect. Go to Menu > Network > Manual Setup, select your Wi-Fi, choose 'Forget'. Then reconnect by selecting it again and entering the password fresh.
IF THAT DIDN'T WORK Change your router's Wi-Fi channel, especially if you're on 2.4GHz. Congestion from neighbors can cause drops. Log into your router and set the 2.4GHz channel to 1, 6, or 11.
HEADS UP This model has a mediocre Wi-Fi card. For reliable streaming, use a wired Ethernet connection if possible, or a dual-band Wi-Fi extender placed close to the TV.