You can troubleshoot in the following ways:

• Check the internet connection of your home Wi-Fi.
• Ensure that your home Wi-Fi password has not been changed.
• Avoid using a metal faceplate on the wall switch, as it may reduce the Wi-Fi signal.
• Restart the switch by pressing the restart button.
• If all other methods fail, press and hold the power button for 5 seconds to restore factory settings, and then try to add the device again.