Web site timing out

[waters]

    I am having an issue with one particular web site that I can't figure out.  When I try to access the site it just eventually times out.  In my troubleshooting I tried accessing the same web site from a device in my DMZ to see if it could be a policy issue.  The web site worked on the DMZ device.

    I created a policy for my PC that allowed all traffic out to the Internet with no web filtering or IPS or anything.  The web site did't work.  I then thought about giving my PC an external IP address and assigning a policy allowing HTTP and HTTPS to the virtual IP of my PC and then the web site worked.  As soon as I disable that policy the web site stops working.

    I have done packet captures with that policy activated and deactivated.  When it is activated I get the normal handshake and then I get a TCP Window Update from the web server and then my PC does the HTTP Get.  When the policy is deactivated it does the normal handshake but then I get my PC issuing TCP ZeroWindowProbes and then it does a reset.

    Is there something different with this web site (snopes.com) that could be causing this behavior?  I don't know of any other web sites having an issue.  Is there something else I can look at to figure out what is happening?  I am using NAT from my internal network out to the Internet.

    I believe the web site was working until recently.  I don't know if it would have anything to do with it but I recently upgraded the firmware to v5.2.9 build736.

    Any suggestions would be greatly appreciated.  Thanks.