I am currently visiting family, and have brought my Chromecast to use in my room. I've brought it here many times before without issues.
This time, however I have been unable to connect the device to the house's WiFi, as the Home app shows the device as offline. The screen on the TV is connected and showing the usual code to get started.
I've tried restarting the router, rebooting my Chromecast, forgetting my home network, although I'm not sure it worked, since it is still listed when I look at device info. I feel like I'm running out of options at this point...
Thanks for reaching out and for being a step ahead of us. Let's check this further.
What's the LED status on your Chromecast? Could you please try to 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.
If the issue still persists, please factory reset your Chromecast.
Let me know how it goes.