Diagnosis
The thermostat is failing to join your wireless network. Common causes are incorrect credentials, a weak signal, or incompatible network security settings.
How to Fix It
Follow this checklist. First, ensure your router is broadcasting a 2.4 GHz network. This model does not support 5 GHz. During setup, select your 2.4 GHz SSID. Second, enter the Wi-Fi password precisely. Passwords are case-sensitive. Third, check signal strength. The thermostat requires a strong signal. Use a phone to check bars at the thermostat location. If weak, consider a Wi-Fi extender. Fourth, temporarily disable any MAC address filtering on your router until setup is complete.
If That Didn't Work
Your router's security protocol may be incompatible. The RTH6580WF supports WPA/WPA2-Personal (AES/TKIP). It does not support WPA3 or enterprise-level security. Access your router's settings and ensure the 2.4 GHz band is using WPA2-Personal (AES). Try the connection again.
Heads Up
A factory reset of the thermostat's network settings can clear a corrupted configuration. Press and hold the Fan and Up arrow buttons for 5 seconds until the Wi-Fi icon flashes. This clears only network info, not your schedule or settings.