Hey SKA, Jaffar,
My apologies for the delayed reply. I wanted to reach out and ensure you are good to go. If you are running into the N260 error code, a C wire or Nest Power Connector is recommended for your thermostat, as it is not being powered properly. I would recommend having either installed to ensure the device is powered and working properly. Please let me know if you have any questions from here.
It looks like we haven't heard back from the OP so I'm going to go ahead and lock the thread. If you have any further questions or concerns, feel free to create a new thread.
Have a great day,