Nest 3 thermostat does not see my wi-fi

[ams228]

I have 4 identical 3rd gen thermostats all on the same wi-fi network and all installed at the same time about 2 years ago.

Three of the four thermostats work perfectly and I can control them from my Android Pixel 7 Pro phone and from my desktop. 

The 4th unit (the one causing the trouble) can be controlled manually but not on my phone or my desktop both of which say OFFLINE. 

I have started and restarted my router several times to no avail but I have not done a factory reset since not being at all technical,  I'm not sure I will know how to get the thermostat working again with all the deleted information back and at least now I can get heat by manually adjusting the thermostat.

Can you please give me some guidance and / or suggest something else I might try.

[zoeuvre]

Hi ams228, 

Uh-oh! I'm sorry to hear that your thermostat appears to be offline in the app, and for my late response. Let me take a look at this for you. A few questions:

1. Are other non-Nest devices in the home offline?
2. Can the device find or detect other networks?
3. Has there been any recent change in the home Wi-Fi network?
4. Is the Wi-Fi router or access point within a reasonable range (1 to 15 meters) of between three to fifty feet from the Nest devices?

I'll look forward to your response. 

Best,

Zoe

[ams228]

Hi and thank you for investigating my issue.  Answers to your questions appear below:

1.  No other devices in our house are offline

2. The device in question can not detect other networks

3. There have not been any changes in our home Wi-Fi network for years

4. Yes, everything is well within range and my other 3 identical thermostats  (which were all installed at the same time) are working just fine

[zoeuvre]

Hi there, 

Thanks for getting back to us. Kindly restart your thermostat display by detaching it from the base and restarting it by hand. If the symptom persists, then I recommend you factory reset the Nest Thermostat. 

Regards,

Zoe

[ams228]

Thank you your response, but can you explain what you mean by "restarting it by hand" ?

[zoeuvre]

Hello ams228, 

I'm sorry for the confusion—detach the display from the base and restart it while holding it.

Thanks,

Zoe