exception on JaxRpc invoke: HTTP transport error: javax.xml.soap.SOAPException: java.security.PrivilegedActionException: oracle.j2ee.ws.saaj.ContentTypeException: Not a valid SOAP Content-Type: text/html; charset=UTF-8

We got below error while making webservice call to third party (Siebel)
<summary>

exception on JaxRpc invoke: HTTP transport error: javax.xml.soap.SOAPException: java.security.PrivilegedActionException: oracle.j2ee.ws.saaj.ContentTypeException: Not a valid SOAP Content-Type: text/html; charset=UTF-8

</summary>

Solution: Please check third party system's server, there might be server restart or application of some patch.