org.camunda.bpm.engine.ProcessEngineException: Unknown property used in expression: ${Policy.productType}. Cause: Cannot resolve identifier 'Policy'
    at org.camunda.bpm.engine.impl.el.JuelExpression.getValue(JuelExpression.java:63)
    at org.camunda.bpm.engine.impl.el.JuelExpression.getValue(JuelExpression.java:51)
    at org.camunda.bpm.engine.impl.el.ElValueProvider.getValue(ElValueProvider.java:40)
    at org.camunda.bpm.engine.impl.core.variable.mapping.InputParameter.execute(InputParameter.java:46)
    at org.camunda.bpm.engine.impl.core.variable.mapping.IoParameter.execute(IoParameter.java:51)
    at org.camunda.bpm.engine.impl.core.variable.mapping.IoMapping.executeInputParameters(IoMapping.java:39)
    at org.camunda.bpm.engine.impl.pvm.runtime.PvmExecutionImpl.executeIoMapping(PvmExecutionImpl.java:224)
    at org.camunda.bpm.engine.impl.pvm.runtime.PvmExecutionImpl.enterActivityInstance(PvmExecutionImpl.java:1232)
    at org.camunda.bpm.engine.impl.pvm.runtime.operation.PvmAtomicOperationActivityInstanceStart.eventNotificationsStarted(PvmAtomicOperationActivityInstanceStart.java:41)
    at org.camunda.bpm.engine.impl.pvm.runtime.operation.PvmAtomicOperationActivityInstanceStart.eventNotificationsStarted(PvmAtomicOperationActivityInstanceStart.java:35)
    at org.camunda.bpm.engine.impl.core.operation.AbstractEventAtomicOperation.execute(AbstractEventAtomicOperation.java:43)
    at org.camunda.bpm.engine.impl.interceptor.AtomicOperationInvocation.execute(AtomicOperationInvocation.java:99)
    at org.camunda.bpm.engine.impl.interceptor.CommandInvocationContext.invokeNext(CommandInvocationContext.java:131)
    at org.camunda.bpm.engine.impl.interceptor.CommandInvocationContext.performNext(CommandInvocationContext.java:111)
    at org.camunda.bpm.engine.impl.interceptor.CommandInvocationContext.performOperation(CommandInvocationContext.java:86)
    at org.camunda.bpm.engine.impl.persistence.entity.ExecutionEntity.performOperation(ExecutionEntity.java:646)
    at org.camunda.bpm.engine.impl.persistence.entity.ExecutionEntity.performOperation(ExecutionEntity.java:620)
    at org.camunda.bpm.engine.impl.pvm.runtime.operation.PvmAtomicOperationActivityStartCreateScope.scopeCreated(PvmAtomicOperationActivityStartCreateScope.java:43)
    at org.camunda.bpm.engine.impl.pvm.runtime.operation.PvmAtomicOperationCreateScope.execute(PvmAtomicOperationCreateScope.java:54)
    at org.camunda.bpm.engine.impl.pvm.runtime.operation.PvmAtomicOperationCreateScope.execute(PvmAtomicOperationCreateScope.java:28)
    at org.camunda.bpm.engine.impl.interceptor.AtomicOperationInvocation.execute(AtomicOperationInvocation.java:99)
    at org.camunda.bpm.engine.impl.interceptor.CommandInvocationContext.invokeNext(CommandInvocationContext.java:131)
    at org.camunda.bpm.engine.impl.interceptor.CommandInvocationContext.performNext(CommandInvocationContext.java:118)
    at org.camunda.bpm.engine.impl.interceptor.CommandInvocationContext$1.call(CommandInvocationContext.java:102)
    at org.camunda.bpm.engine.impl.interceptor.CommandInvocationContext$1.call(CommandInvocationContext.java:100)
    at org.camunda.bpm.engine.impl.context.ProcessApplicationClassloaderInterceptor.call(ProcessApplicationClassloaderInterceptor.java:48)
    at org.camunda.bpm.application.AbstractProcessApplication.execute(AbstractProcessApplication.java:121)
    at org.camunda.bpm.application.AbstractProcessApplication.execute(AbstractProcessApplication.java:132)
    at org.camunda.bpm.engine.impl.context.Context.executeWithinProcessApplication(Context.java:206)
    at org.camunda.bpm.engine.impl.interceptor.CommandInvocationContext.performNext(CommandInvocationContext.java:100)
    at org.camunda.bpm.engine.impl.interceptor.CommandInvocationContext.performOperation(CommandInvocationContext.java:86)
    at org.camunda.bpm.engine.impl.interceptor.CommandInvocationContext.performOperation(CommandInvocationContext.java:76)
    at org.camunda.bpm.engine.impl.jobexecutor.AsyncContinuationJobHandler.execute(AsyncContinuationJobHandler.java:81)
    at org.camunda.bpm.engine.impl.jobexecutor.AsyncContinuationJobHandler.execute(AsyncContinuationJobHandler.java:40)
    at org.camunda.bpm.engine.impl.persistence.entity.JobEntity.execute(JobEntity.java:131)
    at org.camunda.bpm.engine.impl.cmd.ExecuteJobsCmd.execute(ExecuteJobsCmd.java:109)
    at org.camunda.bpm.engine.impl.cmd.ExecuteJobsCmd.execute(ExecuteJobsCmd.java:42)
    at org.camunda.bpm.engine.impl.interceptor.CommandExecutorImpl.execute(CommandExecutorImpl.java:28)
    at org.camunda.bpm.engine.impl.interceptor.CommandContextInterceptor.execute(CommandContextInterceptor.java:110)
    at org.camunda.bpm.engine.impl.interceptor.ProcessApplicationContextInterceptor.execute(ProcessApplicationContextInterceptor.java:70)
    at org.camunda.bpm.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:33)
    at org.camunda.bpm.engine.impl.jobexecutor.ExecuteJobHelper.executeJob(ExecuteJobHelper.java:57)
    at org.camunda.bpm.engine.impl.jobexecutor.ExecuteJobsRunnable.executeJob(ExecuteJobsRunnable.java:110)
    at org.camunda.bpm.engine.impl.jobexecutor.ExecuteJobsRunnable.run(ExecuteJobsRunnable.java:71)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: org.camunda.bpm.engine.impl.javax.el.PropertyNotFoundException: Cannot resolve identifier 'Policy'
    at org.camunda.bpm.engine.impl.juel.AstIdentifier.eval(AstIdentifier.java:83)
    at org.camunda.bpm.engine.impl.juel.AstProperty.eval(AstProperty.java:52)
    at org.camunda.bpm.engine.impl.juel.AstEval.eval(AstEval.java:50)
    at org.camunda.bpm.engine.impl.juel.AstNode.getValue(AstNode.java:26)
    at org.camunda.bpm.engine.impl.juel.TreeValueExpression.getValue(TreeValueExpression.java:114)
    at org.camunda.bpm.engine.impl.delegate.ExpressionGetInvocation.invoke(ExpressionGetInvocation.java:40)
    at org.camunda.bpm.engine.impl.delegate.DelegateInvocation.proceed(DelegateInvocation.java:58)
    at org.camunda.bpm.engine.impl.delegate.DefaultDelegateInterceptor.handleInvocationInContext(DefaultDelegateInterceptor.java:92)
    at org.camunda.bpm.engine.impl.delegate.DefaultDelegateInterceptor.handleInvocation(DefaultDelegateInterceptor.java:63)
    at org.camunda.bpm.engine.impl.el.JuelExpression.getValue(JuelExpression.java:60)