I have tried performing a factory reset on my Comcast. After doing this the Google Home app still does not recognize the device. I recently moved and I’m trying to set this up on a new Netwerk. Prior to my move Chromecast is working just fine on my old not work. I am not sure how to get the home app to recognize my Chromecast so I can set it up with my new network information.
Thanks for reaching out. What's the LED status on your Chromecast? Please 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.
Let me know how it goes.