AC1200 Dual Band WiFi Range Extender and Helix Fi 2 Gateway Connection failure

I own a Helix Fi 2 Gateway Router/Modem and want to extend the wi-fi range with the AC1200 Band extender from Netgear.  Unfortunately it does not work.  Pressing the WPS buttons on both devices does not connect them.

Also Web Browser Setup does not show the NEW EXTENDER SETUP button or anything explained in the manual.

How can I connect the two devices ?