Thermostat displays E7 and Wi‑Fi or cloud connectivity is lost; remote control via app fails.

Safety first: No high-voltage work is required, but avoid opening the thermostat housing beyond the user-removable portion.

• Step 1 – Check local Wi‑Fi: Verify other devices can connect to the same Wi‑Fi network and access the internet. Reboot your router and modem.
• Step 2 – Move router or add extender: If the thermostat is far from the router, relocate the router closer or add a Wi‑Fi extender to improve signal strength.
• Step 3 – Rejoin network: On the thermostat, go to Wi‑Fi settings, forget the current network, and re-add it by entering the correct password. Ensure you are using a supported band (typically 2.4 GHz).
• Step 4 – Check firewall settings: Ensure your router is not blocking outbound ports or using parental controls that could prevent the thermostat from reaching Carrier servers.
• Step 5 – Factory reset (last resort): If E7 persists, perform a factory reset on the thermostat and reconfigure Wi‑Fi and Carrier app pairing.
• When to call a pro: If the thermostat cannot see any Wi‑Fi networks while other devices can, the internal Wi‑Fi module may be defective and the thermostat may need replacement.