Thanks for the help here, davidking.
Tisha204, how's it going? Were you able to connect your Chromecast to the new network? You can try to reboot your Chromecast and reinstall the Google Home app. If the issue persists, reset your Chromecast and manually connect to the Chromecast SSID. Here's how: Go to the phone settings > Open Wi-Fi and connect to the Chromecast SSID (Example: Chromecast1234, Living Room TV, Bedroom TV, etc.) > Go to the Google Home app and try to set it up again.