Problem accessing Website inside network

I have a web server that sits outside a firewall and can be accessed from inside the firewall. Recently access to the corp website from inside the firewall (Intel 3110) is not possible. Name resolution is not the issue because you cannot access by IP address. The site is fully accessible from the Internet. There are no rules blocking port 80 traffic nor are any IP’s blocked. You can watch the name resolve to the IP and then the browser just hangs. The error is “Cannot find server”. You can ping the web address no problem and tracert the IP. ?????????