!
error Honeywell
Error Code E43
No internet connection. The thermostat cannot communicate with Total Connect Comfort service.
? What Causes This
Internet connection is down, network cable unplugged, or router is not connected to the internet.
✓ How to Fix It
- Make sure the Internet cable is plugged in.
- Reboot the router.
- Verify internet connectivity on other devices.
Source: page 62 of the official manual
From the manual
This error code appears in:
Honeywell RTH6580WF Wi-Fi Smart Thermostat