Reference:
Based on the exhibit, the administrator has configured the FortiGuard Category Based Filter to block access to all social networking sites, and has also configured a Static URL Filter to block access to twitter.com. As a result, users are being redirected to a block page when they try to access twitter.com. To allow users to access twitter.com while blocking all other social networking sites, the administrator can make the following configuration change: On the Static URL Filter configuration, set Action to Exempt: By setting the Action to Exempt, the administrator can override the block on twitter.com that was specified in the FortiGuard Category Based Filter. This will allow users to access twitter.com, while all other social networking sites will still be blocked.