Hi All,
We are working on a POC to Integrate Siebel to Salesforce through the Webservices.
1. We have generated the Salesfoce Enterprise WSDL.
2. Imported into Siebel, it will create a outbound Webservices.
3. Used the login api call to get the sessionId and Serverurl - we are done this without any issues and able to retrieve the sessionId and endpoint url.
4. Used the create api call with above session id, we are getting the below error - HTTP Request error during 'Submitting Data SendHTTP request': 'Status code - 500'
With the same Input xml through SOAP UI or POSTMAN, it is working fine.

below is the XML

 <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:urn="urn:enterprise.soap.sforce.com" xmlns:urnl="urn:sobject.enterprise.soap.sforce.com">
   <soapenv:Header>
    <urn:SessionHeader>
           <urn:sessionId>111111111111111</urn:sessionId>
           </urn:SessionHeader>  
   </soapenv:Header>
     <soapenv:Body>
      <urn:create>
         <!--Zero or more repetitions:-->
         <urn:sObjects    xsi:type="urn1:Account" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
            <!--Zero or more repetitions:-->
            <Name>TestWebservice</Name>
            <Description>TestWebservice</Description>
        </urn:sObjects>
      </urn:create>
     </soapenv:Body>
 </soapenv:Envelope>
 
  Is any firewall issue between Siebel to Salesforce?.or XML issue or Do we need to define siebel url as connected app in Salesforce?
 Appreciated your help.
 
 Thanks,
 Naren