If your Chromecast is still connected to an existing Wi-Fi network, you can follow these steps to change the Wi-Fi network it is connected to.
If you've already changed to a different Wi-Fi network, try these steps:
If these steps above don’t solve the issue, you’ll need to factory reset your Chromecast, then set it up again using your new Wi-Fi network and password. If you're using Chromecast with Google TV, follow these setup steps instead.
Instead of factory resetting your Chromecast, if you're comfortable changing your router settings, you can change your new Wi-Fi network name and password in your router's settings to be the same as the previous ones. Your device should then automatically connect to the Wi-Fi.
Checking back in to see if you still need help with this. Feel free to respond to this thread if you have additional questions or concerns and I'd be glad to answer it for you.
Due to inactivity, I'll go ahead and lock this thread in 24 hours. Feel free to start a new thread if you need assistance with your Google speakers and we'd be glad to assist you further.