MAC Address filtering
If your router has MAC Address filtering enabled, you'll need to add the MAC address of your Chromecast to the list of filtered devices. Your Chromecast’s MAC id is listed at the bottom of the setup app when going through initial setup step.
If you wish to connect your Chromecast without using Wi-Fi and have an available Ethernet connection nearby, you might benefit from using the Ethernet adapter.
Elise is a Chromecast expert and author of this help page. Leave her feedback below about the page.