Nest thermostat shows E10 and cannot connect to Wi‑Fi

Note: E10 affects remote control and app connectivity but does not usually stop local HVAC control.

• Check Wi‑Fi signal: Stand near the Nest with a smartphone and check Wi‑Fi strength. If weak, move the router closer, add a mesh node, or use a Wi‑Fi extender.
• Verify network settings: Ensure your router is broadcasting 2.4 GHz (for older Nest models) and using WPA2 or WPA3 security. Avoid hidden SSIDs and captive portals.
• Re-enter Wi‑Fi credentials: On the Nest, go to Settings > Network, forget the current network, and reconnect by carefully entering the correct password.
• Reboot router and Nest: Power cycle your router and modem, then remove and reattach the Nest display to reboot it.

If E10 persists and other devices connect fine, the Nest Wi‑Fi radio may be defective and the display module may need replacement.