Nest learning thermostat completely dead

[Bigroy]

My nest learning thermostat has been working great until noticed it showed offline 

So I have worked and worked now for hours to try to get on line, every device in home is on line, now completely dead!!! No lights no nothing total darkness on dial

[bradbort]

Have you checked if your furnace is turned off, or a fuse is blown? If power turns off to the furnace, the nest will also be unpowered. 

[laurentbourg]

It most likely ran out of battery for some reason and need further diagnosis. Try removing it from the wall and plug a micro usb to its back outlet to charge it and go from there.