At least for us the problem was located in the http.php file of wordpress, where they validate the URL. The problem is the gethostbyname function of PHP. Test this function with a small script and an external url, if you don’t get an IP, than it is the same problem. It is related to the proxy and dns server. We fixed it by giving static IP adresses for the requested urls in the /etc/hosts.
But this is interesting to here, thanks! Can you give me a hint, what you did in the SSL-Scanning Proxy part? I can not find something useful, when I google it.
Maybe it is helpful, I obeserved also an error for fetching data from RSS feeds with the WordPress RSS Feed Retriever. It seems to be the same problem.
Is there already a solution? I have the same problem.
