The following detailed checks can be performed on the client server computers:
Common errors - if your workstations have problems contacting the Internet through Web Security, perform the common connection checks on the client computers and on the Client Site Proxy server
User Proxy Settings - Check that the user has the correct proxy setting for the CSP server, including the port number that the CSP listens on.
If you use an internal DNS name for the CSP, ensure that the client system can resolve this name. Test whether the client computer can resolve the DNS name by performing an nslookup of the name of the CSP.