I would suggest trying the following troubleshooting steps:
Check if the Nest thermostat is still connected to your Wi-Fi network. If it is not, you will need to reconnect it to the network before you can control it through the Google Home app.
Try accessing the Nest thermostat through the Nest app, which is a separate app from the Google Home app. If you can access the thermostat through the Nest app, there may be an issue with the integration between the Nest and Google Home apps.
Restart your phone and the Google Home app. Sometimes, simply restarting the app or your phone can resolve temporary glitches or connectivity issues.
Make sure that your Google Home app is up to date. You can check for updates in the Google Play Store or App Store, depending on your device.
If these steps do not resolve the issue, you may need to contact Nest support for further assistance. They can provide you with specific troubleshooting steps for your particular issue, or help you determine if there is a hardware problem with your Nest thermostat.
I hope this information helps you regain control of your Nest thermostat. Let me know if you have any further questions or concerns.
