Make sure the setup hasn't already been completed using another Apple account, such as a friend or family member's iPhone. If someone has already installed the products using their iPhone, they should send you an invitation so you can share access to the products via the Apple Home app. Ask your friend or family member to go: in the Home + Control app settings, select "Guests" and click "Invite a user". If yours is the first Apple account to access the setup, reset the Wi-Fi and HomeKit settings stored in the thermostat by pressing the side button in the bottom right corner for 5 seconds until you hear a beep (see "How to reset Apple HomeKit on my Smarther with Netatmo connected thermostat?").
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