If you continue to see the W5 help code after restarting your thermostat, the best thing to do is contact support. Make sure you have the help code and your thermostat’s serial number ready to go before your call. To find your thermostat’s serial number, pull the display off the base and flip it over. The serial number is above the QR code on the back of the display. When you reach an agent, be sure to let them know you've already tried restarting your thermostat.
Troubleshoot a Nest thermostat W5 code - Google Nest Help
