DIAGNOSIS The provisioning process is failing due to phone location services, VPN/proxy interference, or an incompatible router security protocol.
FIX Use the exact setup sequence. Enable phone Bluetooth and Location Services before starting. Connect your phone to the 2.4 GHz Wi-Fi band. During setup, when prompted, connect directly to the thermostat's temporary network (starts with "AMZN").
IF THAT DIDN'T WORK Temporarily change your router's Wi-Fi security to WPA2-Personal (AES). Disable any guest network isolation, AP isolation, or client isolation features. Disable any VPN or ad-blocker on your phone.
HEADS UP The thermostat does not support WPA3-only security or captive portals (like in apartments). If your network uses these, setup will always fail.