What if I’m seeing an ‘Unexpected Error’ message during the Accessory Setup using an iOS smart device?

An "Unexpected Error Occurred" indicates one or more of the connection / registration steps failed. Please verify the following:

• You are connected to your home WiFi on your mobile device and airplane mode is on (not using mobile data).
• You are within 5-10 feet of the thermostat throughout the connection process.
• Your mobile device has the most recent version of the Resideo App, and is running the latest OS/iOS version.

Once these steps are completed, force close and reopen the Resideo App and try again.

For more information, please see this article.