Enabling SSL / TLS on an InterSystems (soap) web service, part 2

We are in the process of setting enabling SSL on a soap web service exposed via InterSystems, but are running into trouble. We have installed our certificates on our webserver (Apache 2.4) and enabled SSL over the default port 57772. However, we now get an error when sending a soap message to the web service (it used to work over http). Specifically the CSP gateway refuses to route te emssage the soap web service:

<SOAP-ENV:Envelope SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:s="http://www.w3.org/2001/XMLSchema">

  <SOAP-ENV:Body>

     <SOAP-ENV:Fault>

        <faultcode>SOAP-ENV:Server</faultcode>

        <faultstring>CSP Gateway Error (version:2016.1.2.209.0 build:1601.1554e)</faultstring>

        <detail>

           <error xmlns="http://tempuri.org">

              <special>Systems Management</special>

              <text>Invalid Request : Cannot identify application path</text>

           </error>

        </detail>

     </SOAP-ENV:Fault>

  </SOAP-ENV:Body>

</SOAP-ENV:Envelope>

Probably either the CSP gateway or the web server was misconfigured. Anyone an idea in which direction we might look. (BTW accessing the management port now returns the same error as does using SSL port 443).

PS this issue was also submitted to WRC