i can't get the ecobee lite to connect during setup, it just spins on 'connecting to server'

Diagnosis

The "connecting to server" infinite loop on the ecobee Smart Thermostat Lite typically indicates a failure in the TLS handshake or a DNS resolution error between the device and the ecobee cloud servers. While the device may show a strong Wi-Fi signal, it is unable to establish a secure socket connection. This is frequently caused by a mismatch between the thermostat's expected network protocol and the router's security settings, specifically when "Smart Connect" or "Band Steering" is enabled, forcing the device to jump between 2.4GHz and 5GHz frequencies during the critical registration phase.

Another common culprit is a restrictive firewall or a DNS provider (like some ISP defaults) that cannot resolve the specific ecobee API endpoints. If the device is stuck spinning, it means the hardware is functional and the local Wi-Fi connection is established, but the authentication packet is being dropped or ignored by the server. You can confirm this by checking if other 2.4GHz IoT devices are experiencing similar latency or if you have a "Guest Network" enabled that might be isolating the device from the primary gateway.

How to Fix It

Follow these precise steps to clear the network cache and force a clean handshake with the ecobee servers:

1. Power cycle the thermostat by pulling it off the wall backplate for 30 seconds and then snapping it back in. This clears the temporary volatile memory.
2. On the device screen, navigate to Main Menu > Settings > Reset.
3. Select Reset Registration. Confirm the action. This wipes the unique registration token and forces the device to request a new ID from the server.
4. Access your router settings via a web browser. Temporarily disable "Band Steering" or "Smart Connect" so that the 2.4GHz and 5GHz bands have distinct SSIDs (e.g., "Home_WiFi" and "Home_WiFi_5G").
5. On the ecobee Lite, go to Main Menu > Settings > Wi-Fi and connect specifically to the 2.4GHz network. The Lite model is significantly more stable on 2.4GHz during the initial registration.
6. Once connected to the 2.4GHz band, wait 60 seconds. If it still spins, restart your modem and router by unplugging them for 60 seconds to clear the ARP cache.
7. Attempt the registration process again. Once the "Success" message appears, you can re-enable Band Steering if desired, though keeping a dedicated 2.4GHz SSID is recommended for IoT stability.

If That Didn't Work

• Change DNS Providers: Log into your router and change the DNS settings from your ISP's default to Google DNS (8.8.8.8 and 8.8.4.4) or Cloudflare (1.1.1.1). Many ecobee connection loops are solved by bypassing restrictive ISP DNS filters that block the server's registration port.
• Disable IPv6: Some newer Mesh routers (like Eero or Orbi) use IPv6 by default, which can cause routing loops for the ecobee Lite. Disable IPv6 in the router's advanced network settings and force IPv4 only to see if the connection completes.
• Create a Dedicated IoT Guest Network: Set up a separate 2.4GHz Guest Network with WPA2-AES encryption (avoid WPA3 for the initial setup). Connect the ecobee to this isolated network to bypass any complex firewall rules or VLAN restrictions on your main network.
• Check for MAC Filtering: If you have MAC address filtering enabled on your router, the ecobee will be blocked regardless of the password. Find the MAC address in the ecobee's About menu and add it to your router's "Allowed" list.

Heads Up

• Avoid using special characters (like !, @, #) in your Wi-Fi SSID or password; the ecobee Lite's network stack can occasionally misinterpret these, leading to authentication failures.
• Ensure the thermostat is not mounted directly against a large metal surface or a mirror, as this creates a "Faraday cage" effect that weakens the signal just enough to drop the server handshake.
• Keep your router firmware updated. Outdated WPA2 implementations on older routers often conflict with the updated security certificates used by ecobee servers.
• If you are using a VPN at the router level, disable it during setup. The ecobee server may flag the VPN IP as suspicious and block the registration request.