If not you may need to call in. To solve this issue you must check the following.
Nest Thermostat Glitch Leaves Users In The Cold The New
Nest not charging on wall. At this time the battery may still not be strong enough to get the nest connected to your networkthis is normal and eventually the nest will charge itself up enough to return itself to the network. This step will take about 1 hour to fully charge the nest. If you have fuses make sure none have been blown and need replacing. I would check the furnace wiring to make sure they match up and the common wire is the correct wire. They didnt go into detail why but if nest says dont do it do not do it. The nest appears only to charge when the ac system is running robbing a small amount to charge itself.
Double check whether the nest display is ideally placed to the based check whether the system gets enough power make sure the system is compatible check the thermostats wiring find whether the fuse in the system blown out look whether the. It will deplete if the system is off for too long. Depending on the model you have it will be either mini or micro usb. After an hour of charging return the nest to the wall and it should resume working. If the nest thermostat isnt charging after power has been restored to your home check your breaker box to see that all switches are in the on position. Check on the nest itself under settingstechnical infopower.
Regular thermostat it can work fine with battery ones. If the voltage is low there may be a wiring problem and your nest may not be charging properly. If it works properly with a normal thermostat then it should work okay with the nest you need a common wire. Do not try to restart your thermostat while its still connected to a computer for charging. Pull off the nest display and use the usb port on the back to charge it with a usb cable and wall charger. It should be around 24v from the red wire r.
After it starts up plug the usb cable back in to finish charging the nest. Unplug it from the wall then plug it back in to see if that helps. Do not use a. If your nest thermostat is off and wont turn on take the thermostat off the base and charge it using a usb cord plugged into a wall charger or a computer.