The MagniFi MAX might be setup properly but the Google Home App has stopped working.
1 - Try closing the Google Home app and re-launch it.
2 - Open a music source such as Pandora and press the "Chromecast" button in the App.
• You should see a pop-up button that says "Cast to MagniFi MAX".
• If not, you need to close the Google Home app and try again.
You may need to check your phone’s Wi-Fi settings and manually change back to your home’s Wi-Fi network.