To reset your gateway you have to push and hold the reset button on the back of the gateway and release the button in one of the following reset-modes:

LED lights green: reset WLAN/WiFi settings.
LED lights orange: reset WLAN/WiFi settings and the user-password.
LED lights red: reset to factory settings.

Important: Release the reset button when the LED has the color of the reset mode, to execute this reset mode.