Here is a list of some troubleshooting steps you can take to identify the issue and resolve it, if possible:

1. Reboot your modem and router by unplugging them for 30 seconds or more, and then plugging them back in.
2. Restart your device (e.g., computer, phone, tablet, etc.).
3. Check for any loose connections between the Chromecast and the TV or its power source.
4. Check that the Chromecast, modem, and router are all within range and not too far apart.
5. Go to a website such as www.speedtest.net or www.fast.com and check to see if your internet speed is within a suitable range for streaming video (at least 5 Mbps for SD videos, at least 25 Mbps for HD videos).
6. If your speed test results are not up to satisfactory levels, contact your internet service provider and have them look into it.