DHL - HTTP XML Request

Dear Make Community,

I am having a hard time, connection to this API in XML with my HTTP module.

Thats what my current configuration looks like, but since I have never used a XML call before I am not sure how to fix it.

I am sure that my basic auth credentials are correct as well as my header since I was able to connect with a JSON call for another endpoint.

Any help is highly appreciated!

No one, that is able to help me out here?