It looks like there is an issue with some version of SoapClient, and SSL. There have been a couple instances where the connection to the HTTPS Web Services have stopped connecting, but HTTP works perfectly fine. I have now put in place that HTTPS is not required for Web Services just in case you do run into this issue.
A solution I have seen would be to update your version of OpenSSL on the server to the latest one, given you have access or your server administrator is willing to do this.
