What happens when you try to add it? Are there any error messages or codes? Let's try these steps:
Make sure the Nest Wifi point is in the "ready to set up" status, and is showing a slow pulsing white light. If you're using the older Google Wifi, it should be slow pulsing blue light instead. If you're seeing a different light status, first factory reset it.
Place your Nest Wifi or Google Wifi point in an area that is not more than 2 rooms away from your Nest Wifi router or primary Wifi point.
Next, close the Google Home app and ensure Location Services and Bluetooth are turned ON on the phone or tablet you're using.
Turn OFF mobile/cell data.
Make sure the mobile device you're using is already connected to your Wifi network.
Open the Google Home app and follow the steps in the "Add a point or an additional router" section of this help article. If you're using the older Google Wifi, follow the steps the "Add an additional point" section of this help article instead.
If the same issue persists, do a full network restart to re-establish connections:
Disconnect the power and the Ethernet cable from the Nest Wifi router or primary Wifi point.
Disconnect the power from all your Nest Wifi or Google Wifi points.
Disconnect the power adapter from the modem.
Allow all devices to stay disconnected from the power for 2 to 3 minutes.
Once done, connect the power back to the modem only, and wait for it to fully back up (all lights should be lit up before moving to the next step).
After the modem is back online, connect the Ethernet cable back to the Nest Wifi router or primary Google Wifi point''s WAN port (globe symbol).
Connect the power back to the Nest Wifi router or primary Wifi point, and to your Nest Wifi or Google Wifi points. Wait until they're all fully back on.
Once done, check the status of your router and points in the app. If necessary, retry setup for the one you're trying to add to the network.
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