Google Nest Community

I contacted support and after they couldn't resolve it they triggered the replacement process.

I called support. I found the number in this thread.1 855 469 6378 

Sadly it only worked for a short time for me too. As of a few minutes ago I have a replacement on the way.

I just got of with support. They had me do something I hadn't seen in the self-help stuff and it worked. Press and hold the thermostat for 10 seconds (probably won't take that long) and the thermostat will restart. Mine connected to WiFi after it cam...