2.4 GHz WiFi devices not connecting to Nighthawk X65 AC3000 Tri-Band WiFi Range Extender

Pucrchased a Nighthawk X65 AC3000 Tri-Band WiFi Range Extender about a month ago, (and no I do not have a copy of the reciept) ...

 

I'm just now trying to set the extender up.

 

The Client Link LED lights up for my 5 GHz devices, but the LED will not for my 2.4GHz devices.  (And there appears to be no range gain for my 2.4GHz devices) 

 

So how do I get my 2.4GHz devices to connect to the Extender?

 

Any help or suggestions would be greatly appreciated.

 

Thanks, and best regards,

Michael