I am newbie to Pega and i am using the latest PE for learning.. When i hit 'Submit ' button to run a case , the following  error is displayed:

"There has been an issue; please consult your system administrator" Checking the error in the tracer viewer log , it ihe  "com.pega.pegarules.pub.PRRuntimeException" as per title above

Logs:

Name    Exception [600]    
RULE-OBJ-ACTIVITY WORK- COMMITWITHERRORHANDLING #20180713T133047.594 GMT        
ActivityName    COMMITWITHERRORHANDLING    
ActivityNumber    18    
Break    Breakpoint    
CorrelationID    HM4KZK3DCRSHGDC1CMF6O4O9SJ04JY36OA    
DateTime    20220928T174330.329 GMT    
EventKey    RULE-OBJ-ACTIVITY WORK- COMMITWITHERRORHANDLING #20180713T133047.594 GMT    
EventName    Exception    
EventType    Exception    
ExceptionTrace    java.lang.RuntimeException: com.pega.pegarules.pub.PRRuntimeException: Encountered database exception when committing operation <insert instance TCB-EMEA-ZIM-TCBAPP-WORK T-2014 not only if new>    
FirstInput    Activity=FinishAssignment    
Interaction    52    
JavaStackTrace    java.lang.RuntimeException: com.pega.pegarules.pub.PRRuntimeException: Encountered database exception when committing operation <insert instance TCB-EMEA-ZIM-TCBAPP-WORK T-2014 not only if new>
    at com.pega.pegarules.data.internal.access.DatabaseImpl.commit(DatabaseImpl.java:2197)
    at com.pega.pegarules.data.internal.access.DatabaseImpl.commit(DatabaseImpl.java:2124)
    at com.pegarules.generated.activity.ra_action_commitwitherrorhandling_663a578384fcc69efadf2473d5dbfc39.step4_circum0(ra_action_commitwitherrorhandling_663a578384fcc69efadf2473d5dbfc39.java:522)
    at com.pegarules.generated.activity.ra_action_commitwitherrorhandling_663a578384fcc69efadf2473d5dbfc39.perform(ra_action_commitwitherrorhandling_663a578384fcc69efadf2473d5dbfc39.java:127)
    at com.pega.pegarules.session.internal.mgmt.Executable.doActivity(Executable.java:2850)
    at com.pega.pegarules.session.internal.mgmt.Executable.invokeActivity(Executable.java:11439)
    at com.pegarules.generated.activity.ra_action_workcommit_831f9b05908e4e9b7562054e154dc90d.step3_circum0(ra_action_workcommit_831f9b05908e4e9b7562054e154dc90d.java:426)
    at com.pegarules.generated.activity.ra_action_workcommit_831f9b05908e4e9b7562054e154dc90d.perform(ra_action_workcommit_831f9b05908e4e9b7562054e154dc90d.java:110)
    at com.pega.pegarules.session.internal.mgmt.Executable.doActivity(Executable.java:2850)
    at com.pega.pegarules.session.internal.mgmt.Executable.invokeActivity(Executable.java:11439)
    at com.pegarules.generated.activity.ra_action_finishassignment_e8fe2003e3b7eb82d467c7515e2139c4.step19_circum0(ra_action_finishassignment_e8fe2003e3b7eb82d467c7515e2139c4.java:2134)
    at com.pegarules.generated.activity.ra_action_finishassignment_e8fe2003e3b7eb82d467c7515e2139c4.perform(ra_action_finishassignment_e8fe2003e3b7eb82d467c7515e2139c4.java:391)
    at com.pega.pegarules.session.internal.mgmt.Executable.doActivity(Executable.java:2850)
    at com.pega.pegarules.session.internal.mgmt.base.ThreadRunner.runActivitiesAlt(ThreadRunner.java:653)
    at com.pega.pegarules.session.internal.mgmt.PRThreadImpl.runActivitiesAlt(PRThreadImpl.java:519)
    at com.pega.pegarules.session.internal.engineinterface.service.HttpAPI.runActivities(HttpAPI.java:4303)
    at com.pega.pegarules.session.external.engineinterface.service.EngineAPI.processRequestInner(EngineAPI.java:445)
    at sun.reflect.GeneratedMethodAccessor103.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.pega.pegarules.session.internal.PRSessionProviderImpl.performTargetActionWithLock(PRSessionProviderImpl.java:1391)
    at com.pega.pegarules.session.internal.PRSessionProviderImpl.doWithRequestorLocked(PRSessionProviderImpl.java:1123)
    at com.pega.pegarules.session.internal.PRSessionProviderImpl.doWithRequestorLocked(PRSessionProviderImpl.java:977)
    at com.pega.pegarules.session.external.engineinterface.service.EngineAPI.processRequest(EngineAPI.java:368)
    at com.pega.pegarules.session.internal.engineinterface.service.HttpAPI.invoke(HttpAPI.java:930)
    at com.pega.pegarules.session.internal.engineinterface.etier.impl.EngineImpl._invokeEngine_privact(EngineImpl.java:338)
    at com.pega.pegarules.session.internal.engineinterface.etier.impl.EngineImpl.invokeEngine(EngineImpl.java:282)
    at com.pega.pegarules.session.internal.engineinterface.etier.impl.EngineImpl.invokeEngine(EngineImpl.java:259)
    at com.pega.pegarules.priv.context.JNDIEnvironment.invokeEngineInner(JNDIEnvironment.java:281)
    at com.pega.pegarules.priv.context.JNDIEnvironment.invokeEngine(JNDIEnvironment.java:226)
    at com.pega.pegarules.web.impl.WebStandardImpl.invokeEngine(WebStandardImpl.java:837)
    at com.pega.pegarules.web.impl.WebStandardImpl.makeEtierRequest(WebStandardImpl.java:797)
    at com.pega.pegarules.web.impl.WebStandardImpl.doPostInner(WebStandardImpl.java:420)
    at sun.reflect.GeneratedMethodAccessor100.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.pega.pegarules.internal.bootstrap.PRBootstrap.invokeMethod(PRBootstrap.java:388)
    at com.pega.pegarules.internal.bootstrap.PRBootstrap.invokeMethodPropagatingThrowable(PRBootstrap.java:430)
    at com.pega.pegarules.boot.internal.extbridge.AppServerBridgeToPega.invokeMethodPropagatingThrowable(AppServerBridgeToPega.java:225)
    at com.pega.pegarules.boot.internal.extbridge.AppServerBridgeToPega.invokeMethod(AppServerBridgeToPega.java:274)
    at com.pega.pegarules.internal.web.servlet.WebStandardBoot.doPost(WebStandardBoot.java:164)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
    at com.pega.pegarules.internal.web.servlet.WebStandardBoot.service(WebStandardBoot.java:191)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)
Caused by: com.pega.pegarules.pub.PRRuntimeException: Encountered database exception when committing operation <insert instance TCB-EMEA-ZIM-TCBAPP-WORK T-2014 not only if new>
    at com.pega.pegarules.data.internal.access.UpdateProcessor.performOps(UpdateProcessor.java:1855)
    at com.pega.pegarules.data.internal.access.UpdateProcessor.action(UpdateProcessor.java:288)
    at com.pega.pegarules.data.internal.access.UpdateProcessor.action(UpdateProcessor.java:101)
    at com.pega.pegarules.data.internal.store.DataStoreManager.doInTransaction(DataStoreManager.java:273)
    at com.pega.pegarules.data.internal.access.UpdateProcessor.processUpdates(UpdateProcessor.java:218)
    at com.pega.pegarules.data.internal.access.DatabaseImpl.commit(DatabaseImpl.java:2162)
    ... 65 more
Caused by: com.pega.pegarules.pub.clipboard.WrongModeException: property 'ContactNumbers' is defined as a column but is of mode String Group instead of required mode String
    at com.pega.pegarules.data.internal.access.PageDatabaseMapperImpl.fillInStatementFromPageWithStream(PageDatabaseMapperImpl.java:1304)
    at com.pega.pegarules.data.internal.store.ManagedTransaction.getStatementWithPrepValues(ManagedTransaction.java:1000)
    at com.pega.pegarules.data.internal.store.ManagedTransaction.addBatchRdbms(ManagedTransaction.java:906)
    at com.pega.pegarules.data.internal.store.ManagedTransaction.performUpdate(ManagedTransaction.java:789)
    at com.pega.pegarules.data.internal.access.Saver.saveInstance(Saver.java:934)
    at com.pega.pegarules.data.internal.access.Saver.saveInstance(Saver.java:876)
    at com.pega.pegarules.data.internal.access.UpdateProcessor.performOps(UpdateProcessor.java:1534)
    ... 70 more    
LastStep    WORK- COMMITWITHERRORHANDLING #20180713T133047.594 GMT Step: 4 Circum: 0    
NodeID    444183a2baab41bc92604cc073a419db    
NodeName    DESKTOP-GN1PIP1    
ParameterPageContent        
ParameterPageName    =unnamed=    
PrimaryPageClass    TCB-EMEA-ZIM-TCBApp-Work-TCB    
PrimaryPageContent        
PrimaryPageName    pyWorkPage    
RequestorID    HM4KZK3DCRSHGDC1CMF6O4O9SJ04JY36OA    
Sequence    599    
StepNumber    4    
ThreadName    PS2__TABTHREAD0    
WorkPool    TCB-EMEA-ZIM-TCBApp-Work