Nest worked yesterday, now “no power” message

[NCWildcat]

Good morning- Our Nest was functioning fine for the five months we’ve been in our new house, but yesterday afternoon, it stopped functioning. There’s a no power error message (E268) that I’m receiving and I can’t seem to find the cure.  I changed out the batteries, restarted the Wi-Fi router, and reconnected one of the two floors on the Home app.  There weren’t any weather events or other house trauma, so I’m at a loss.  I looked at the fuse box as well, and nothing seems to have tripped any fuses.  Short of calling in a tech, does anyone have any other suggestions??

Thanks!
(also, for some reason, the Home app is having trouble reconnecting with the second floor thermostat, which also hadn’t happened before.)

[Rwiinbo]

Hi, NCWildcat! Just a few questions to help you. The common error E can sometimes (but not always) be a problem with your device's power supply, a disconnected cable, a cable plugged into the wrong socket, or a cable with a broken internal circuit (unlikely, but it happens). Could you please send us a photo of your error code and the model of your Nest Thermostat?

[virnab]

Hi NCWildcat,

Thanks for reaching out to our community.

I understand that your Nest thermostat has been functioning perfectly for the past five months since you moved into your new house. However, it stopped working yesterday afternoon and is showing a "No power" error message (E268). Additionally, I see that you are having trouble reconnecting the thermostat on the second floor to the Google Home app. I appreciate you detailing the troubleshooting steps you have already taken to address these inconveniences. No worries, help is here.

Thank you Rwiinbo for your contribution on this thread.

To assist you better, please answer these questions:

• What Nest thermostat model devices do you have? For your reference, you can check out this article on how to tell which Nest thermostat you have.
• What's the make and model of your heating, ventilation, and air conditioning (HVAC) equipment?
• Are the power breakers on, and are you receiving power to your home?
• Is the display correctly seated and locked in the base?
• Are all wires securely connected to the terminals, with no loose or exposed strands?
• Do you have a common ground wire or C wire?
• Are you familiar with the C wire?
• Have you experienced any power outages within the last few days or weeks?
• Could you please share with us a picture of your thermostat’s wiring and the controller board wiring?
• Does the thermostat charge with a USB cable?

• Are you using an Android or an iPhone device to control your thermostat devices?
• Is your mobile device updated?
• Is your Google Home app updated?
• How far from the router is your second-floor thermostat?
• Do you have a Google account?
• Have there been any recent changes to the network or equipment?
• Are any other devices experiencing issues with the WiFi connection on the second floor?
• What network do you currently use, 2.4 GHz or 5 GHz?

Please keep me posted.

Best regards,

Virna