Yo tenía el mismo problema, mi Google Chromecast no se conectaba al WiFi
ni podía ver las redes disponibles- Lo solucioné cortando la corriente
eléctrica a la unidad principal y luego de unos segundos lo volví a
conectar.
I had the same problem, my Google Chromecast wouldn't connect to WiFi
and I couldn't see available networks. I solved it by cutting off the
power to the main unit and after a few seconds I reconnected it.