Park Call Soft Keys not working

I was able to set up 2 park locations that display on our Poly Phones, however I cannot get them to work. 1) The lines do not blink or light at all to indicate that a call is parked there 2) you cannot pick up the parked call by hitting the soft key, we simply get an error message "Call is no longer available to pick up", but if you dial in to the park location the call is actually still there. Anyone have any solutions?