Below error was received when invoking Siebel IP15 Web Service through php client (Web Application). In Soap request Session Type was set to None. Error Code: 10944642 Error Message: Error: Inbound SOAP Message - Session Token is missing or invalid or has expired. Siebel will only ask for Session Token when calling web service with Session Type Stateless. On investigation it was clear that we need to add below parameters to eai.cfg file to run web service with Session Type None. AllowAnonymous = TRUE Impersonate = False Search for AllowAnonUsers in cfg and paste above parameters under it. CFG can be found on path: C:\Siebel\15.0.0.0.0\ses\siebsrvr\BIN\enu Save the cfg file and restart the Siebel services and test. Soap Header: <soapenv:Header> <UsernameToken xmlns="http://siebel.com/webservices">username</UsernameToken> <PasswordText xmlns="http://siebel.com/webservices">pass...