I have a user who can't get to my web site hosted on AWS EC2. This user is behind a corporate proxy server, and when they enter my URL, they get a "The proxy server isn't responding" message in IE and my apache logs show HTTP 408 results from their IP address.
The site requires SSL client certificates. It's an apache http server.
Other users are able to get to the web site just fine, and the user behind the proxy server is able to access other sites that require SSL client certificates.
Is there anything I can do to debug this from my end? If I can avoid it, I'd rather not have to make him chase down the issue on his end.