AOSS Button not working on WZR 1750DHPD

[BuffaloSpringfield]

I am trying to connect a WiFi range extender to my Buffalo AirStation. When I press the AOSS button on the AirStation nothing happens. None of the lights on the front blink including the wireless LED. 

I am hoping there is a setting I can change but don't want to experiment changing anything. I don't know which settings affect the AOSS or how to change them. Please let me know which settings are important for the AOSS and I can tell you how they are set.

The signal goes through a Comcast router that Comcast set up as a slave to the AirStation. The AirStation is wired to my desktop computer and two VoIP phones (Polycom IP331).