EP::500 internal server error ::while accessing ESS on EP

while user trying to connect through EP he is getting 500 internal server error ,even server is up and running and the backend system also running fine.

Please suggest us what we can check ::

Full exception chain ::

java.lang.NullPointerException

at com.sap.xss.per.fc.persinfo.FcPersInfo.CreateOverview(FcPersInfo.java:1156)

at com.sap.xss.per.fc.persinfo.wdp.InternalFcPersInfo.CreateOverview(InternalFcPersInfo.java:940)

at com.sap.xss.per.fc.persinfo.FcPersInfoInterface.CreateOverview2(FcPersInfoInterface.java:312)

at com.sap.xss.per.fc.persinfo.FcPersInfoInterface.CreateOverview(FcPersInfoInterface.java:296)

at com.sap.xss.per.fc.persinfo.wdp.InternalFcPersInfoInterface.CreateOverview(InternalFcPersInfoInterface.java:325)

at com.sap.xss.per.fc.persinfo.wdp.InternalFcPersInfoInterface$External.CreateOverview(InternalFcPersInfoInterface.java:561)

at com.sap.xss.hr.per.de.family.overview.BizCardsView.wdDoModifyView(BizCardsView.java:156)

at com.sap.xss.hr.per.de.family.overview.wdp.InternalBizCardsView.wdDoModifyView(InternalBizCardsView.java:341)

at com.sap.tc.webdynpro.progmodel.generation.DelegatingView.doModifyView(DelegatingView.java:78)

at com.sap.tc.webdynpro.progmodel.view.View.modifyView(View.java:337)

at com.sap.tc.webdynpro.clientserver.cal.ClientComponent.doModifyView(ClientComponent.java:481)

at com.sap.tc.webdynpro.clientserver.cal.ClientComponent.doModifyView(ClientComponent.java:488)

at com.sap.tc.webdynpro.clientserver.window.WindowPhaseModel.doModifyView(WindowPhaseModel.java:551)

at com.sap.tc.webdynpro.clientserver.window.WindowPhaseModel.processRequest(WindowPhaseModel.java:148)

at com.sap.tc.webdynpro.clientserver.window.WebDynproWindow.processRequest(WebDynproWindow.java:335)

at com.sap.tc.webdynpro.clientserver.cal.AbstractClient.executeTasks(AbstractClient.java:143)

at com.sap.tc.webdynpro.clientserver.session.ApplicationSession.doProcessing(ApplicationSession.java:333)

at com.sap.tc.webdynpro.clientserver.session.ClientSession.doApplicationProcessingPortal(ClientSession.java:761)

at com.sap.tc.webdynpro.clientserver.session.ClientSession.doApplicationProcessing(ClientSession.java:696)

at com.sap.tc.webdynpro.clientserver.session.ClientSession.doProcessing(ClientSession.java:253)

at com.sap.tc.webdynpro.clientserver.session.RequestManager.doProcessing(RequestManager.java:149)

at com.sap.tc.webdynpro.clientserver.session.core.ApplicationHandle.doProcessing(ApplicationHandle.java:73)

at com.sap.tc.webdynpro.portal.pb.impl.AbstractApplicationProxy.sendDataAndProcessActionInternal(AbstractApplicationProxy.java:869)

at com.sap.tc.webdynpro.portal.pb.impl.AbstractApplicationProxy.create(AbstractApplicationProxy.java:229)

at com.sap.portal.pb.PageBuilder.updateApplications(PageBuilder.java:1344)

at com.sap.portal.pb.PageBuilder.createPage(PageBuilder.java:356)

at com.sap.portal.pb.PageBuilder.init(PageBuilder.java:549)

at com.sap.portal.pb.PageBuilder.wdDoInit(PageBuilder.java:193)

at com.sap.portal.pb.wdp.InternalPageBuilder.wdDoInit(InternalPageBuilder.java:150)

at com.sap.tc.webdynpro.progmodel.generation.DelegatingComponent.doInit(DelegatingComponent.java:108)

at com.sap.tc.webdynpro.progmodel.controller.Controller.initController(Controller.java:215)

at com.sap.tc.webdynpro.progmodel.controller.Controller.init(Controller.java:200)

at com.sap.tc.webdynpro.clientserver.cal.ClientComponent.init(ClientComponent.java:430)

at com.sap.tc.webdynpro.clientserver.cal.ClientApplication.init(ClientApplication.java:362)

at com.sap.tc.webdynpro.clientserver.session.ApplicationSession.initApplication(ApplicationSession.java:783)

at com.sap.tc.webdynpro.clientserver.session.ApplicationSession.doProcessing(ApplicationSession.java:303)

at com.sap.tc.webdynpro.clientserver.session.ClientSession.doApplicationProcessingStandalone(ClientSession.java:741)

at com.sap.tc.webdynpro.clientserver.session.ClientSession.doApplicationProcessing(ClientSession.java:694)

at com.sap.tc.webdynpro.clientserver.session.ClientSession.doProcessing(ClientSession.java:253)

at com.sap.tc.webdynpro.clientserver.session.RequestManager.doProcessing(RequestManager.java:149)

at com.sap.tc.webdynpro.serverimpl.defaultimpl.DispatcherServlet.doContent(DispatcherServlet.java:62)

at com.sap.tc.webdynpro.serverimpl.defaultimpl.DispatcherServlet.doPost(DispatcherServlet.java:53)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)

at com.sap.engine.services.servlets_jsp.server.HttpHandlerImpl.runServlet(HttpHandlerImpl.java:401)

at com.sap.engine.services.servlets_jsp.server.HttpHandlerImpl.handleRequest(HttpHandlerImpl.java:266)

at com.sap.engine.services.httpserver.server.RequestAnalizer.startServlet(RequestAnalizer.java:386)

at com.sap.engine.services.httpserver.server.RequestAnalizer.startServlet(RequestAnalizer.java:364)

at com.sap.engine.services.httpserver.server.RequestAnalizer.invokeWebContainer(RequestAnalizer.java:1039)

at com.sap.engine.services.httpserver.server.RequestAnalizer.handle(RequestAnalizer.java:265)

at com.sap.engine.services.httpserver.server.Client.handle(Client.java:95)

at com.sap.engine.services.httpserver.server.Processor.request(Processor.java:175)

at com.sap.engine.core.service630.context.cluster.session.ApplicationSessionMessageListener.process(ApplicationSessionMessageListener.java:33)

at com.sap.engine.core.cluster.impl6.session.MessageRunner.run(MessageRunner.java:41)

at com.sap.engine.core.thread.impl3.ActionObject.run(ActionObject.java:37)

at java.security.AccessController.doPrivileged(Native Method)

at com.sap.engine.core.thread.impl3.SingleThread.execute(SingleThread.java:104)

at com.sap.engine.core.thread.impl3.SingleThread.run(SingleThread.java:176)