I went through links like: SOAPFaultException “MustUnderstand headers (oasis-200401-wss-wssecurity-secext-1.0.xsd) are not understood”, but still struggling. I’m using Spring Boot v2.2.2..RELEASE and SOAP project. I am loading two different WSDL file into my project. One URL Generates to http://localhost:8080/employee/employee-soap which works fine. But http://localhost:8080/student/student-soap this gives below error. 2020-02-17 15:31:00.241 WARN 20236 — [nio-8080-exec-5] o.s.w.soap.server.SoapMessageDispatcher : Could not handle mustUnderstand headers: