diff --git a/service/history/task/cross_cluster_source_task_executor.go b/service/history/task/cross_cluster_source_task_executor.go
index 059a9725411..b1c2dba7505 100644
--- a/service/history/task/cross_cluster_source_task_executor.go
+++ b/service/history/task/cross_cluster_source_task_executor.go
@@ -257,10 +257,6 @@ func (t *crossClusterSourceTaskExecutor) executeCancelExecutionTask(
 
 		if failedCause != nil {
 			// remaining errors are non-retryable
-			cause := types.CancelExternalWorkflowExecutionFailedCauseUnknownExternalWorkflowExecution
-			if *failedCause == types.CrossClusterTaskFailedCauseWorkflowAlreadyCompleted {
-				cause = types.CancelExternalWorkflowExecutionFailedCauseWorkflowAlreadyCompleted
-			}
 			return requestCancelExternalExecutionFailed(
 				ctx,
 				taskInfo,
@@ -269,7 +265,6 @@ func (t *crossClusterSourceTaskExecutor) executeCancelExecutionTask(
 				taskInfo.TargetWorkflowID,
 				taskInfo.TargetRunID,
 				now,
-				cause,
 			)
 		}
 		return requestCancelExternalExecutionCompleted(
@@ -484,10 +479,6 @@ func (t *crossClusterSourceTaskExecutor) executeSignalExecutionTask(
 
 		if failedCause != nil {
 			// remaining errors are non-retryable
-			cause := types.SignalExternalWorkflowExecutionFailedCauseUnknownExternalWorkflowExecution
-			if *failedCause == types.CrossClusterTaskFailedCauseWorkflowAlreadyCompleted {
-				cause = types.SignalExternalWorkflowExecutionFailedCauseWorkflowAlreadyCompleted
-			}
 			return signalExternalExecutionFailed(
 				ctx,
 				taskInfo,
@@ -497,7 +488,6 @@ func (t *crossClusterSourceTaskExecutor) executeSignalExecutionTask(
 				taskInfo.TargetRunID,
 				signalInfo.Control,
 				now,
-				cause,
 			)
 		}
 
diff --git a/service/history/task/cross_cluster_source_task_executor_test.go b/service/history/task/cross_cluster_source_task_executor_test.go
index 78b7afa01b9..916e962d9ee 100644
--- a/service/history/task/cross_cluster_source_task_executor_test.go
+++ b/service/history/task/cross_cluster_source_task_executor_test.go
@@ -664,7 +664,7 @@ func (s *crossClusterSourceTaskExecutorSuite) TestExecuteCancelExecution_Failure
 		&types.CrossClusterTaskResponse{
 			TaskType:    types.CrossClusterTaskTypeCancelExecution.Ptr(),
 			TaskState:   int16(processingStateInitialized),
-			FailedCause: types.CrossClusterTaskFailedCauseWorkflowAlreadyCompleted.Ptr(),
+			FailedCause: types.CrossClusterTaskFailedCauseWorkflowNotExists.Ptr(),
 		},
 		func(
 			mutableState execution.MutableState,
diff --git a/service/history/task/transfer_active_task_executor.go b/service/history/task/transfer_active_task_executor.go
index f5babe3a49f..802bbd646c6 100644
--- a/service/history/task/transfer_active_task_executor.go
+++ b/service/history/task/transfer_active_task_executor.go
@@ -630,7 +630,6 @@ func (t *transferActiveTaskExecutor) processCancelExecution(
 			task.TargetWorkflowID,
 			task.TargetRunID,
 			t.shard.GetTimeSource().Now(),
-			types.CancelExternalWorkflowExecutionFailedCauseUnknownExternalWorkflowExecution,
 		)
 		return err
 	}
@@ -657,11 +656,6 @@ func (t *transferActiveTaskExecutor) processCancelExecution(
 			// for retryable error just return
 			return err
 		}
-		cause := types.CancelExternalWorkflowExecutionFailedCauseUnknownExternalWorkflowExecution
-		var alreadyCompletedErr *types.WorkflowExecutionAlreadyCompletedError
-		if errors.As(err, &alreadyCompletedErr) {
-			cause = types.CancelExternalWorkflowExecutionFailedCauseWorkflowAlreadyCompleted
-		}
 		return requestCancelExternalExecutionFailed(
 			ctx,
 			task,
@@ -670,7 +664,6 @@ func (t *transferActiveTaskExecutor) processCancelExecution(
 			task.TargetWorkflowID,
 			task.TargetRunID,
 			t.shard.GetTimeSource().Now(),
-			cause,
 		)
 	}
 
@@ -757,7 +750,6 @@ func (t *transferActiveTaskExecutor) processSignalExecution(
 			task.TargetRunID,
 			signalInfo.Control,
 			t.shard.GetTimeSource().Now(),
-			types.SignalExternalWorkflowExecutionFailedCauseUnknownExternalWorkflowExecution,
 		)
 	}
 
@@ -777,17 +769,12 @@ func (t *transferActiveTaskExecutor) processSignalExecution(
 			tag.TargetWorkflowRunID(task.TargetRunID),
 			tag.Error(err))
 
-		// Check to see if the error is non-transient, in which case add RequestCancelFailed
+		// Check to see if the error is non-transient, in which case add SignalFailed
 		// event and complete transfer task by setting the err = nil
 		if common.IsServiceTransientError(err) || common.IsContextTimeoutError(err) {
 			// for retryable error just return
 			return err
 		}
-		var alreadyCompletedErr *types.WorkflowExecutionAlreadyCompletedError
-		cause := types.SignalExternalWorkflowExecutionFailedCauseUnknownExternalWorkflowExecution
-		if errors.As(err, &alreadyCompletedErr) {
-			cause = types.SignalExternalWorkflowExecutionFailedCauseWorkflowAlreadyCompleted
-		}
 		return signalExternalExecutionFailed(
 			ctx,
 			task,
@@ -797,7 +784,6 @@ func (t *transferActiveTaskExecutor) processSignalExecution(
 			task.TargetRunID,
 			signalInfo.Control,
 			t.shard.GetTimeSource().Now(),
-			cause,
 		)
 	}
 
@@ -1433,7 +1419,6 @@ func requestCancelExternalExecutionFailed(
 	targetWorkflowID string,
 	targetRunID string,
 	now time.Time,
-	cause types.CancelExternalWorkflowExecutionFailedCause,
 ) error {
 
 	err := updateWorkflowExecution(ctx, wfContext, true,
@@ -1454,7 +1439,7 @@ func requestCancelExternalExecutionFailed(
 				targetDomain,
 				targetWorkflowID,
 				targetRunID,
-				cause,
+				types.CancelExternalWorkflowExecutionFailedCauseUnknownExternalWorkflowExecution,
 			)
 			return err
 		},
@@ -1479,7 +1464,6 @@ func signalExternalExecutionFailed(
 	targetRunID string,
 	control []byte,
 	now time.Time,
-	cause types.SignalExternalWorkflowExecutionFailedCause,
 ) error {
 
 	err := updateWorkflowExecution(ctx, wfContext, true,
@@ -1501,7 +1485,7 @@ func signalExternalExecutionFailed(
 				targetWorkflowID,
 				targetRunID,
 				control,
-				cause,
+				types.SignalExternalWorkflowExecutionFailedCauseUnknownExternalWorkflowExecution,
 			)
 			return err
 		},
diff --git a/service/history/task/transfer_active_task_executor_test.go b/service/history/task/transfer_active_task_executor_test.go
index c4f81196eb1..3d8e54a3fb6 100644
--- a/service/history/task/transfer_active_task_executor_test.go
+++ b/service/history/task/transfer_active_task_executor_test.go
@@ -1046,7 +1046,7 @@ func (s *transferActiveTaskExecutorSuite) TestProcessCancelExecution_Success() {
 	)
 }
 
-func (s *transferActiveTaskExecutorSuite) TestProcessCancelExecution_EntityNotExistsError() {
+func (s *transferActiveTaskExecutorSuite) TestProcessCancelExecution_Failure() {
 	s.testProcessCancelExecution(
 		s.targetDomainID,
 		func(
@@ -1067,27 +1067,6 @@ func (s *transferActiveTaskExecutorSuite) TestProcessCancelExecution_EntityNotEx
 	)
 }
 
-func (s *transferActiveTaskExecutorSuite) TestProcessCancelExecution_WorkflowAlreadyCompleted() {
-	s.testProcessCancelExecution(
-		s.targetDomainID,
-		func(
-			mutableState execution.MutableState,
-			workflowExecution, targetExecution types.WorkflowExecution,
-			event *types.HistoryEvent,
-			transferTask Task,
-			requestCancelInfo *persistence.RequestCancelInfo,
-		) {
-			persistenceMutableState, err := test.CreatePersistenceMutableState(mutableState, event.ID, event.Version)
-			s.NoError(err)
-			s.mockExecutionMgr.On("GetWorkflowExecution", mock.Anything, mock.Anything).Return(&persistence.GetWorkflowExecutionResponse{State: persistenceMutableState}, nil)
-			cancelRequest := createTestRequestCancelWorkflowExecutionRequest(s.targetDomainName, transferTask.GetInfo().(*persistence.TransferTaskInfo), requestCancelInfo.CancelRequestID)
-			s.mockHistoryClient.EXPECT().RequestCancelWorkflowExecution(gomock.Any(), cancelRequest).Return(&types.WorkflowExecutionAlreadyCompletedError{}).Times(1)
-			s.mockHistoryV2Mgr.On("AppendHistoryNodes", mock.Anything, mock.Anything).Return(&persistence.AppendHistoryNodesResponse{}, nil).Once()
-			s.mockExecutionMgr.On("UpdateWorkflowExecution", mock.Anything, mock.Anything).Return(&persistence.UpdateWorkflowExecutionResponse{MutableStateUpdateSessionStats: &persistence.MutableStateUpdateSessionStats{}}, nil).Once()
-		},
-	)
-}
-
 func (s *transferActiveTaskExecutorSuite) TestProcessCancelExecution_Duplication() {
 	s.testProcessCancelExecution(
 		s.targetDomainID,
@@ -1223,7 +1202,7 @@ func (s *transferActiveTaskExecutorSuite) TestProcessSignalExecution_Success() {
 	)
 }
 
-func (s *transferActiveTaskExecutorSuite) TestProcessSignalExecution_EntityNotExistsError() {
+func (s *transferActiveTaskExecutorSuite) TestProcessSignalExecution_Failure() {
 	s.testProcessSignalExecution(
 		s.targetDomainID,
 		func(
@@ -1244,26 +1223,6 @@ func (s *transferActiveTaskExecutorSuite) TestProcessSignalExecution_EntityNotEx
 	)
 }
 
-func (s *transferActiveTaskExecutorSuite) TestProcessSignalExecution_WorkflowAlreadyCompletedError() {
-	s.testProcessSignalExecution(
-		s.targetDomainID,
-		func(
-			mutableState execution.MutableState,
-			workflowExecution, targetExecution types.WorkflowExecution,
-			event *types.HistoryEvent,
-			transferTask Task,
-			signalInfo *persistence.SignalInfo,
-		) {
-			persistenceMutableState, err := test.CreatePersistenceMutableState(mutableState, event.ID, event.Version)
-			s.NoError(err)
-			s.mockExecutionMgr.On("GetWorkflowExecution", mock.Anything, mock.Anything).Return(&persistence.GetWorkflowExecutionResponse{State: persistenceMutableState}, nil)
-			signalRequest := createTestSignalWorkflowExecutionRequest(s.targetDomainName, transferTask.GetInfo().(*persistence.TransferTaskInfo), signalInfo)
-			s.mockHistoryClient.EXPECT().SignalWorkflowExecution(gomock.Any(), signalRequest).Return(&types.WorkflowExecutionAlreadyCompletedError{}).Times(1)
-			s.mockHistoryV2Mgr.On("AppendHistoryNodes", mock.Anything, mock.Anything).Return(&persistence.AppendHistoryNodesResponse{}, nil).Once()
-			s.mockExecutionMgr.On("UpdateWorkflowExecution", mock.Anything, mock.Anything).Return(&persistence.UpdateWorkflowExecutionResponse{MutableStateUpdateSessionStats: &persistence.MutableStateUpdateSessionStats{}}, nil).Once()
-		},
-	)
-}
 func (s *transferActiveTaskExecutorSuite) TestProcessSignalExecution_Duplication() {
 	s.testProcessSignalExecution(
 		s.targetDomainID,