This error code usually occurs for one of two reasons: 1) You're not logged into the Mysa app, or 2) there was an error connecting your device to a Mysa account
1. Log in to your Mysa Account
Open the Mysa app, and tap the menu icon in the top right-hand corner. If you see the login button in the top right-hand corner than it means you're not logged in. Login to your Mysa account and see if you can access the restricted settings.
2. Repair HomeKit Permissions
1) Ensure all units are deleted from HomeKit and the Mysa app if they appear there.
2) Locate Mysa in your iPhone settings.
3) Toggle 'Home Data' to 'Off'
4) Factory Reset your unit by pressing firmly on both arrows for fifteen seconds.
5) Open the Mysa app, tap add thermostat and re-connect the thermostats via Apple Pairing.
6) If you wish to use HomeKit, simply go back to your iOS settings toggle back to HomeKit data to 'On' and add Mysa as an accessory in the Apple Home app.