Could you provide more details about this? What code or message are you getting? Also, what specific Nest thermostat do you have? If would also be a great help if you could provide a rundown of the steps you've tried if you've tried some already.
I'll look forward to your response.
I haven't heard from you in a while so I'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community.