The Nest app recognizes all of our thermostats, but it’s saying that one of them isn’t connected to Wifi and is offline, but it’s not. We can control the unit manually on the wall. Any idea what to do? Apparently, people have had this issue, but all of the previous suggestions haven’t worked for us.
I'm having this exact same issue with a nest thermostat E that I installed just yesterday, it was working fine from install until now, saying it has been "offline" only in the NEST app for 1 hour now; in the GOOGLE HOME app not only is it not offline, I can control it from there, just not from the NEST app, this is exclusively a NEST APP issue; thermostat is ONLINE no problem, and controllable from Google Home app just fine, purely showing offline in the Nest app.
Additionally: made a schedule change in the Nest app and confirmed on the thermostat itself that it took the change! Also an extra temperature sensor I have is reporting back the correct temperature as well, so basically all data seems to be flowing to and from between the app / thermostat / sensor; the only problem here is that the app itself is INCORRECTLY reporting that the thermostat is offline, which is also preventing access to many thermostat settings from the app itself... again odd since I can make similar changes from the Google Home app just fine for the same thermostat.
Update: tried restarting the thermostat, no change; tried restarting router, no change; had to actually remove the thermostat from the app and re-add it... and now it's reporting online again just fine... this really should not have had to been done, whatever was wrong with it should be able to be resolved without having to go to that extent 😡
On the upside, I only needed to re-set which sensor for it to use and change the mode back to heat cool, all the rest of my settings appear to have stayed put... super weird.
I have the exact same symptoms you've described. I can control the thermostat with Google Home app but Nest app shows it as offline. None of the troubleshooting steps seem to address this issue directly and have not worked.
Sorry for the late response. I wanted to reach out and see if everyone is good to go. If you have any questions or trouble from here, please feel free to reach back out at any time.