diff --git a/app/services/file_manager/file_upload/upload_client.py b/app/services/file_manager/file_upload/upload_client.py
index 86dc08e3..77421ac0 100644
--- a/app/services/file_manager/file_upload/upload_client.py
+++ b/app/services/file_manager/file_upload/upload_client.py
@@ -167,7 +167,7 @@ def check_upload_duplication(self, file_objects: List[FileObject]) -> Tuple[List
         # generate a list of locations for uploaded files to check duplication
         # at same time, generate a dict of mapping with object_path: FileObject
         locations = [x.object_path for x in file_objects]
-        object_path_file_object_map = {x.object_path: x for x in file_objects}
+        object_path_file_object_map = {x.object_path.lower(): x for x in file_objects}
 
         payload = {
             'locations': locations,
@@ -182,10 +182,16 @@ def check_upload_duplication(self, file_objects: List[FileObject]) -> Tuple[List
         if response.status_code == 200:
             exist_files = response.json().get('result', [])
             for exist_file_path in exist_files:
-                object_path_file_object_map.pop(exist_file_path)
+                object_path_file_object_map.pop(exist_file_path.lower())
         else:
             SrvErrorHandler.default_handle('Error when checking file duplication', if_exit=True)
 
+        # reconstruct non exist file objects which will be uploaded
+        # without lower() function.
+        return_list = {}
+        for _, item in object_path_file_object_map.items():
+            return_list.update({item.object_path: item})
+
         return list(object_path_file_object_map.values()), exist_files
 
     @require_valid_token()
diff --git a/pyproject.toml b/pyproject.toml
index db648cfe..e177743c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "app"
-version = "3.0.3"
+version = "3.0.4"
 description = "This service is designed to support pilot platform"
 authors = ["Indoc Systems"]
 
diff --git a/tests/app/services/file_manager/file_upload/test_upload_client.py b/tests/app/services/file_manager/file_upload/test_upload_client.py
index 21454ee3..a8a386be 100644
--- a/tests/app/services/file_manager/file_upload/test_upload_client.py
+++ b/tests/app/services/file_manager/file_upload/test_upload_client.py
@@ -8,6 +8,8 @@
 from multiprocessing.pool import ThreadPool
 from time import sleep
 
+import pytest
+
 from app.configs.app_config import AppConfig
 from app.services.file_manager.file_upload.models import FileObject
 from app.services.file_manager.file_upload.upload_client import UploadClient
@@ -153,7 +155,8 @@ def test_resumable_pre_upload_failed_with_404(httpx_mock, mocker):
         AssertionError('SystemExit not raised')
 
 
-def test_check_upload_duplication_success(httpx_mock, mocker):
+@pytest.mark.parametrize('case_insensitive', [True, False])
+def test_check_upload_duplication_success(httpx_mock, mocker, case_insensitive):
     mocker.patch(
         'app.services.user_authentication.token_manager.SrvTokenManager.decode_access_token',
         return_value=decoded_token(),
@@ -167,12 +170,12 @@ def test_check_upload_duplication_success(httpx_mock, mocker):
     httpx_mock.add_response(
         method='POST',
         url=url,
-        json={'result': [dup_obj.object_path]},
+        json={'result': [dup_obj.object_path.upper() if case_insensitive else dup_obj.object_path]},
     )
 
     not_dup_list, dup_list = upload_client.check_upload_duplication([dup_obj, not_dup_object])
     assert not_dup_list == [not_dup_object]
-    assert dup_list == [dup_obj.object_path]
+    assert dup_list == [dup_obj.object_path.upper() if case_insensitive else dup_obj.object_path]
 
 
 def test_check_upload_duplication_fail_with_500(httpx_mock, mocker, capfd):