I already have a mesh of 3 Google wifi points. I just bought a fourth. When I try to add the new point via the Google Home app, I start the setup process, the app is able to find the new device, but when I select the device to set up, it goes through the "connecting to wifi" process and ultimately fails and says "can not connect to device." I've already done two factory resets on the new point. (Though when I hold the reset button down for 10 seconds, I don't get the orange light the web says I'll see, instead it flashes white before going solid blue and resetting)
1. What exact device, Google Wifi?
2. Is it bought in the same exact country/ region as those you already have? For instalce, mixing US and EU does not work due to differences in Wi-Fi regulations.
3. Have you tried keeping it close to master/ main puck during setup? Eventually ethernet cable it from its' WAN port to master/ main LAN port during setup.
4. Or try the Google Home app with the same Google account from a different Android or Apple device.