Web Services Client fails with ServiceInvocation Exception

[thirupathireddy.gankidi]

DataStage Web Services Client stage fails with below error:

Web_Services_Client_1,0: Fatal Error: Fatal: 0026`:`com.ascentialsoftware.wsclient.ServiceInvocationException: Service invocation exception:
at com.ascentialsoftware.wsclient.WebService.callService(WebService.java:1602)
at com.ascentialsoftware.wsclient.WebService.callService(WebService.java:1544)
at com.ascentialsoftware.wspack.Transformer.process(Transformer.java:105)
at com.ascentialsoftware.jds.StageFactory.runStage(StageFactory.java:544)
at com.ascentialsoftware.jds.StageFactory.runSource(StageFactory.java:335)
Caused by: java.lang.NullPointerException
at com.ascentialsoftware.wsclient.xml.DerivationParser.match(DerivationParser.java:622)
at com.ascentialsoftware.wsclient.xml.DerivationParser.element(DerivationParser.java:367)
at com.ascentialsoftware.wsclient.xml.DerivationParser.segment(DerivationParser.java:271)
at com.ascentialsoftware.wsclient.xml.DerivationParser.segment(DerivationParser.java:293)
at com.ascentialsoftware.wsclient.xml.DerivationParser.segment(DerivationParser.java:208)
at com.ascentialsoftware.wsclient.xml.DerivationParser.expr(DerivationParser.java:171)
at com.ascentialsoftware.wsclient.xml.DerivationParser.parse(DerivationParser.java:138)
at com.ascentialsoftware.wsclient.xml.TreeBuilder.compileRules(TreeBuilder.java:84)
at com.ascentialsoftware.wsclient.MappingHandler.fromArray(MappingHandler.java:304)
at com.ascentialsoftware.wsclient.InputRequest.buildRequestBodyDocument(InputRequest.java:908)
at com.ascentialsoftware.wsclient.WebService.callServiceInternal(WebService.java:1625)
at com.ascentialsoftware.wsclient.WebService.callService(WebService.java:1591)
... 4 more
[dscapiop.C:2169]


Thanks in advance
Thiru

[akrish1982]

check the header of the XML
check the security parameters
check the end point
ping the host
is there a firewall?
is there a need to add an entry to datastage server's host file?
check if the webservice is up and running
test the API from some other SOAP tester