are you clients able to navigate? do you upgrade from os 2.xxx to 3.xxx ? if true thats the problem, the web-proxy isnt present any more for os 3.0 and posibly you mount and old configuration from 2.xxx to 3.xx system,, im not sure of that but it happend to me and i roll back my os to 2.9 system
excuseme for my poor english
Cuando la ignorancia se impone, la razon cordialmente cede el paso.