deleted but can't re-add

[alanmiller3]

I removed my Nest Learning Thermostat (3rd gen) from google home because I thought it was dead and went out and bought a different thermostat.  After figuring out the issue with my HVAC system I plugged the old thermostat back in and it works but I'm having problems getting it setup in the Nest app and Google home again.

1. I reset the thermostat.

2. On the thermostat under Settings, Nest App it says None (which means it's not connected to my Nest account).

3. On the thermostat I configured the wifi and it says connected to the internet.

4. On my phone (which is connected to the same Wifi network) in the Nest App I try to add the device.

    Steps include:

       4a. Add product,

       4b. Continue without scanning

       4c. Select device type, 

       4d. Then you enter the "key" from the back of the device.

    5. Then you select the wifi and it says it's connecting to the device (I see the thermostat's display changes)

    6. On the Nest App, it says connecting and then "Testing network"

    7. At some point I just get the error that says it can't complete.

    8. Then the only option is to click continue on the thermostat and is says refer to nest.com/m15

So what other options are there, a factory reset?

[David_K]

Try these steps:
Troubleshoot an M15 error on a Nest thermostat - Google Nest Help

If the issue persists after trying those steps, reset (not restart) the thermostat and setup from scratch:
Restart or reset a Nest thermostat - Google Nest Help

[alanmiller3 · Accepted solution]

Actually I resolved it by using a different wifi network. I remembered that I had the same issue when I first bought it.

My Google mesh network sits behind my ISP's router and using that network fails (yes, both the nest app on the phone and the thermostat were connected to the same network)

When I use the wifi provided by the ISP router, setup works fine.

After it's setup I just reconfig the thermostat to use my mesh network and all is good.