Here is how to get Chromecast to work if you are on Verizon FiOS and are having trouble connecting.
Step 1: Check WiFi Settings
1. Make sure you have a wired connection to the internet.
2. Turn on Wifi, but don’t connect to a wireless network
3. Go to system preferences and turn on internet sharing. Your configuration should look like the photo above.
Step 2: Create WiFi Network
Create a new network with WPA2 encryption. See photo above.
Step 3: WiFi Confirmation
1. When you have setup your network, the wifi icon on the top menu bar should look like the icon above.
2. Find an Android tablet running v4.1 or later. Connect to the wireless network you just created.
3. Download the Chromecast App from the Google Play store on your tablet.
4. Follow all the onscreen instructions. If successful, you should see the Ready to Cast text in the upper left corner of your TV screen.
5. To test your connection, go to the YouTube app on your tablet. Pick any video and play it. In the upper right corner, you should see a TV/beam icon. Once you press it, Chromecast connects and begins to play your video. At this point you can go do other things on your tablet while the video is playing.