After installing the Web Security for Windows Agent, it is possible that end users may complain that an application that requires Internet access does not function properly (e.g. Babylon dictionary, Windows Update, antivirus software update etc.).
The issue occurs when certain applications use the proxy settings of Internet Explorer and try to contact the Web Security service. As the third party application does not “know” how to authenticate to the Web Security service, it fails to authenticate.
For more information, see Editing a PAC File page.