Scenario: A network engineer has installed a Citrix ADC system into their corporate DMZ and would like to provide access to a web server on the internal LAN. The web server will be accessed by external users through the Citrix ADC. The firewall administrator has opened the relevant ports required on the external and the internal firewall. The engineer notices that the virtual server and services representing the web server are down and the internal web server does NOT appear accessible from the Citrix ADC. What could be the cause of this?