Background:
I am using a CMS which is using xajax. I am also using a proxy server in front of the webserver, which is provided by my hosting provider. The proxy server SSL enables my site without the need for my own certificate. However the proxy also modifies the request.
Reproduce steps:
Call https://sslsites.de/www.my-website.de/cms.php
Then the proxy at sslsites.de calls...