If you wish to cast a video from the youtube.com player but can't find the Cast button in the bottom right corner, try these steps:
- Make sure your laptop is connected to your Wi-Fi network, and your Chromecast is set up and connected to the same network.
- If you can find your Chromecast listed on the Cast extension, you're may be trying to view content that cannot be directly played back on youtube.com. In this case, cast your tab instead.