Is this user allowed access to the Web Proxy ?

Users->AddUser->WebAccess

Selecting the "YES" radio button will enable this user to access the World Wide Web through the Server caching web proxy.  To enable this facility, the user's browser needs to be configured to use a proxy server.  The required proxy setting are:
 

Type
Proxy address to use
Port
HTTP enter the Server host name or IP address 800
Secure leave blank  --
FTP enter the Server host name or IP address 800
Gopher leave blank  --
Socks leave blank  --
WAIS leave blank  --

The default for this option is "NO"