SOAP call to AccountCombinationService via APEX_WEB_SERVICE.make_request returns null

Summary

Using APEX_WEB_SERVICE.make_request to call fscmService/AccountCombinationService but the response returned is NULL

Content

Doing a SOAP call with the payload (listed in bottom) in Postman is working fine.

But when I try to execute same payload from the Oracle database (APEX) via APEX_WEB_SERVICE.make_request it returns NULL.

It should return an XMLTYPE document. I have seen similar issue calling other SOAP services which I solved with fixing the g_request_headers.

But it still does not work for me in this case.

 

Code snippet;

  apex_web_service.g_request_headers.delete; 
  apex_web_service.g_request_headers(1).name := 'Content-Type';