diff --git a/api/core/app/apps/advanced_chat/app_generator.py b/api/core/app/apps/advanced_chat/app_generator.py
index afecd99978..61de9ec670 100644
--- a/api/core/app/apps/advanced_chat/app_generator.py
+++ b/api/core/app/apps/advanced_chat/app_generator.py
@@ -36,7 +36,6 @@ from libs.flask_utils import preserve_flask_contexts
 from models import Account, App, Conversation, EndUser, Message, Workflow, WorkflowNodeExecutionTriggeredFrom
 from models.enums import WorkflowRunTriggeredFrom
 from services.conversation_service import ConversationService
-from services.errors.message import MessageNotExistsError
 from services.workflow_draft_variable_service import DraftVarLoader, WorkflowDraftVariableService
 
 logger = logging.getLogger(__name__)
@@ -480,8 +479,6 @@ class AdvancedChatAppGenerator(MessageBasedAppGenerator):
                 # get conversation and message
                 conversation = self._get_conversation(conversation_id)
                 message = self._get_message(message_id)
-                if message is None:
-                    raise MessageNotExistsError("Message not exists")
 
                 # chatbot app
                 runner = AdvancedChatAppRunner(
diff --git a/api/core/app/apps/agent_chat/app_generator.py b/api/core/app/apps/agent_chat/app_generator.py
index 75a0b00424..edea6199d3 100644
--- a/api/core/app/apps/agent_chat/app_generator.py
+++ b/api/core/app/apps/agent_chat/app_generator.py
@@ -26,7 +26,6 @@ from factories import file_factory
 from libs.flask_utils import preserve_flask_contexts
 from models import Account, App, EndUser
 from services.conversation_service import ConversationService
-from services.errors.message import MessageNotExistsError
 
 logger = logging.getLogger(__name__)
 
@@ -238,8 +237,6 @@ class AgentChatAppGenerator(MessageBasedAppGenerator):
                 # get conversation and message
                 conversation = self._get_conversation(conversation_id)
                 message = self._get_message(message_id)
-                if message is None:
-                    raise MessageNotExistsError("Message not exists")
 
                 # chatbot app
                 runner = AgentChatAppRunner()
diff --git a/api/core/app/apps/chat/app_generator.py b/api/core/app/apps/chat/app_generator.py
index 76fae879f2..a28c106ce9 100644
--- a/api/core/app/apps/chat/app_generator.py
+++ b/api/core/app/apps/chat/app_generator.py
@@ -25,7 +25,6 @@ from factories import file_factory
 from models.account import Account
 from models.model import App, EndUser
 from services.conversation_service import ConversationService
-from services.errors.message import MessageNotExistsError
 
 logger = logging.getLogger(__name__)
 
@@ -224,8 +223,6 @@ class ChatAppGenerator(MessageBasedAppGenerator):
                 # get conversation and message
                 conversation = self._get_conversation(conversation_id)
                 message = self._get_message(message_id)
-                if message is None:
-                    raise MessageNotExistsError("Message not exists")
 
                 # chatbot app
                 runner = ChatAppRunner()
diff --git a/api/core/app/apps/completion/app_generator.py b/api/core/app/apps/completion/app_generator.py
index 7bc4a0a5c0..966a6f1d66 100644
--- a/api/core/app/apps/completion/app_generator.py
+++ b/api/core/app/apps/completion/app_generator.py
@@ -201,8 +201,6 @@ class CompletionAppGenerator(MessageBasedAppGenerator):
             try:
                 # get message
                 message = self._get_message(message_id)
-                if message is None:
-                    raise MessageNotExistsError()
 
                 # chatbot app
                 runner = CompletionAppRunner()
diff --git a/api/core/app/apps/message_based_app_generator.py b/api/core/app/apps/message_based_app_generator.py
index 58b94f4d43..e84d59209d 100644
--- a/api/core/app/apps/message_based_app_generator.py
+++ b/api/core/app/apps/message_based_app_generator.py
@@ -29,6 +29,7 @@ from models.enums import CreatorUserRole
 from models.model import App, AppMode, AppModelConfig, Conversation, EndUser, Message, MessageFile
 from services.errors.app_model_config import AppModelConfigBrokenError
 from services.errors.conversation import ConversationNotExistsError
+from services.errors.message import MessageNotExistsError
 
 logger = logging.getLogger(__name__)
 
@@ -251,7 +252,7 @@ class MessageBasedAppGenerator(BaseAppGenerator):
 
         return introduction or ""
 
-    def _get_conversation(self, conversation_id: str):
+    def _get_conversation(self, conversation_id: str) -> Conversation:
         """
         Get conversation by conversation id
         :param conversation_id: conversation id
@@ -260,11 +261,11 @@ class MessageBasedAppGenerator(BaseAppGenerator):
         conversation = db.session.query(Conversation).filter(Conversation.id == conversation_id).first()
 
         if not conversation:
-            raise ConversationNotExistsError()
+            raise ConversationNotExistsError("Conversation not exists")
 
         return conversation
 
-    def _get_message(self, message_id: str) -> Optional[Message]:
+    def _get_message(self, message_id: str) -> Message:
         """
         Get message by message id
         :param message_id: message id
@@ -272,4 +273,7 @@ class MessageBasedAppGenerator(BaseAppGenerator):
         """
         message = db.session.query(Message).filter(Message.id == message_id).first()
 
+        if message is None:
+            raise MessageNotExistsError("Message not exists")
+
         return message