diff --git a/external/concealer/include/concealer/service_with_validation.hpp b/external/concealer/include/concealer/service_with_validation.hpp
index 9d1b0c23d9b..da002bf25be 100644
--- a/external/concealer/include/concealer/service_with_validation.hpp
+++ b/external/concealer/include/concealer/service_with_validation.hpp
@@ -42,17 +42,7 @@ class ServiceWithValidation
   {
   }
 
-  class TimeoutError : public common::scenario_simulator_exception::Error
-  {
-  public:
-    template <typename... Ts>
-    explicit TimeoutError(Ts &&... xs)
-    : common::scenario_simulator_exception::Error(std::forward<decltype(xs)>(xs)...)
-    {
-    }
-  };
-
-  auto operator()(const typename T::Request::SharedPtr & request, std::size_t attempts_count = 1)
+  auto operator()(const typename T::Request::SharedPtr & request, std::size_t attempts_count)
     -> void
   {
     validateAvailability();
@@ -122,7 +112,7 @@ class ServiceWithValidation
         }
       }
     }
-    throw TimeoutError(
+    throw common::scenario_simulator_exception::Error(
       "Requested the service ", std::quoted(service_name), " ", attempts_count,
       " times, but was not successful.");
   }
diff --git a/external/concealer/src/field_operator_application.cpp b/external/concealer/src/field_operator_application.cpp
index c197d4182d1..3ee855dd3bd 100644
--- a/external/concealer/src/field_operator_application.cpp
+++ b/external/concealer/src/field_operator_application.cpp
@@ -318,10 +318,9 @@ auto FieldOperatorApplication::engage() -> void
       auto request = std::make_shared<Engage::Request>();
       request->engage = true;
       try {
-        return requestEngage(request);
-      } catch (const decltype(requestEngage)::TimeoutError &) {
-        // ignore timeout error because this service is validated by Autoware state transition.
-        return;
+        return requestEngage(request, 1);
+      } catch (const common::Error &) {
+        return;  // Ignore error because this service is validated by Autoware state transition.
       }
     });
   });
@@ -369,10 +368,9 @@ auto FieldOperatorApplication::initialize(const geometry_msgs::msg::Pose & initi
           std::make_shared<autoware_adapi_v1_msgs::srv::InitializeLocalization::Request>();
         request->pose.push_back(initial_pose_msg);
         try {
-          return requestInitialPose(request);
-        } catch (const decltype(requestInitialPose)::TimeoutError &) {
-          // ignore timeout error because this service is validated by Autoware state transition.
-          return;
+          return requestInitialPose(request, 1);
+        } catch (const common::Error &) {
+          return;  // Ignore error because this service is validated by Autoware state transition.
         }
       });
     });
@@ -417,7 +415,7 @@ auto FieldOperatorApplication::plan(const std::vector<geometry_msgs::msg::PoseSt
       request->waypoints.push_back(each.pose);
     }
 
-    requestSetRoutePoints(request);
+    requestSetRoutePoints(request, 1);
 
     waitForAutowareStateToBeWaitingForEngage();
   });
@@ -512,7 +510,7 @@ auto FieldOperatorApplication::sendCooperateCommand(
     request->stamp = latest_cooperate_status_array.stamp;
     request->commands.push_back(cooperate_command);
 
-    task_queue.delay([this, request]() { requestCooperateCommands(request); });
+    task_queue.delay([this, request]() { requestCooperateCommands(request, 1); });
 
     used_cooperate_statuses.push_back(*cooperate_status);
   }