DIAGNOSIS The setup process is getting hung up, usually because your phone is struggling to hand off the Wi-Fi network info to the camera. This is a common hiccup with many smart devices.
FIX You need to reset the process completely. 1) Factory reset the camera by holding down the button on the front for about 10 seconds until you hear the chime. 2) On your phone, forget the Wi-Fi network named "NestCam-XXXX" if it appears. 3) Force close your Google Home app. 4) Restart your phone. 5) Now, with your phone connected to the 2.4GHz band of your Wi-Fi (this is crucial), open the Home app and start setup fresh. Hold your phone very close to the camera during the QR code scan.
IF THAT DIDN'T WORK If it still fails, your router might be blocking the local communication needed for setup. Temporarily disable any "AP Isolation," "Client Isolation," or "Smart Connect" features in your router's settings just for the setup, then re-enable them afterward.
HEADS UP Double-check that you're not trying to connect it to a 5GHz-only guest network. The camera can only connect to a 2.4GHz network. Your main network likely broadcasts both, but the guest network might not.