diff --git a/ntk/decorator.py b/ntk/decorator.py
index 5732168..711960a 100644
--- a/ntk/decorator.py
+++ b/ntk/decorator.py
@@ -37,11 +37,12 @@ def _wrapper(self, *func_args, **func_kwargs):
             response = func(self, *func_args, **func_kwargs)
             error_default = f'{func.__name__.capitalize().replace("_", " ")} of {self.store} failed.'
             error_msg = ""
+            content_type = response.headers.get('content-type', '').lower()
             if response.ok and not response_json:
                 return response
-            elif response.ok and response.headers.get('content-type') == 'application/json':
+            elif response.ok and content_type.startswith('application/json'):
                 return response
-            elif response.headers.get('content-type') == 'application/json':
+            elif content_type.startswith('application/json'):
                 result = response.json()
                 error_msg = " -> "
                 for key, value in result.items():
diff --git a/tests/test_command.py b/tests/test_command.py
index 6d828c4..4f63f4b 100644
--- a/tests/test_command.py
+++ b/tests/test_command.py
@@ -52,7 +52,8 @@ def test_init_command_without_config_file_should_be_required_name_api_key_store_
     @patch("ntk.command.Config.write_config", autospec=True)
     def test_init_command_with_name_and_configs_should_be_call_create_theme_and_save_config(self, mock_write_config):
         self.mock_gateway.return_value.create_theme.return_value.ok = True
-        self.mock_gateway.return_value.create_theme.return_value.headers = {'content-type': 'application/json'}
+        self.mock_gateway.return_value.create_theme.return_value.headers = {
+            'content-type': 'application/json; charset=utf-8'}
         self.mock_gateway.return_value.create_theme.return_value.json.return_value = {
             'id': 1234,
             'name': 'Test Init Theme',
@@ -89,7 +90,8 @@ def test_list_command_without_config_file_should_be_required_api_key_store(self)
     @patch("ntk.command.Config.write_config", autospec=True)
     def test_list_command_with_configs_should_be_show_theme_id_and_theme_name(self, mock_write_config):
         self.mock_gateway.return_value.get_themes.return_value.ok = True
-        self.mock_gateway.return_value.get_themes.return_value.headers = {'content-type': 'application/json'}
+        self.mock_gateway.return_value.get_themes.return_value.headers = {
+            'content-type': 'application/json; charset=utf-8'}
         self.mock_gateway.return_value.get_themes.return_value.json.return_value = {
             "count": 2,
             "next": None,
@@ -131,7 +133,8 @@ def test_list_command_with_missing_theme_should_be_raise_message(
         self, mock_write_config
     ):
         self.mock_gateway.return_value.get_themes.return_value.ok = True
-        self.mock_gateway.return_value.get_themes.return_value.headers = {'content-type': 'application/json'}
+        self.mock_gateway.return_value.get_themes.return_value.headers = {
+            'content-type': 'application/json; charset=utf-8'}
         self.mock_gateway.return_value.get_themes.return_value.json.return_value = {
             "count": 0,
             "next": None,
@@ -173,7 +176,8 @@ def test_checkout_command_with_theme_id_and_configs_should_be_download_file_corr
         self, mock_write_config, mock_open_file
     ):
         self.mock_gateway.return_value.get_templates.return_value.ok = True
-        self.mock_gateway.return_value.get_templates.return_value.headers = {'content-type': 'application/json'}
+        self.mock_gateway.return_value.get_templates.return_value.headers = {
+            'content-type': 'application/json; charset=utf-8'}
         self.mock_gateway.return_value.get_templates.return_value.json.return_value = [
             {
                 "theme": 1234,
@@ -278,7 +282,8 @@ def test_pull_command_with_configs_and_filenames_should_be_download_only_file_in
         self, mock_write_config, mock_open_file
     ):
         self.mock_gateway.return_value.get_template.return_value.ok = True
-        self.mock_gateway.return_value.get_template.return_value.headers = {'content-type': 'application/json'}
+        self.mock_gateway.return_value.get_template.return_value.headers = {
+            'content-type': 'application/json; charset=utf-8'}
         self.mock_gateway.return_value.get_template.return_value.json.return_value = {
             "theme": 1234,
             "name": "assets/image.png",
@@ -319,10 +324,11 @@ def test_watch_command_should_call_gateway_with_correct_arguments_belong_to_file
         self.mock_gateway.return_value.create_or_update_template.return_value.ok = True
         self.mock_gateway.return_value.create_or_update_template.return_value.status_code = 200
         self.mock_gateway.return_value.create_or_update_template.return_value.headers = {
-            'content-type': 'application/json'}
+            'content-type': 'application/json; charset=utf-8'}
         self.mock_gateway.return_value.delete_template.return_value.ok = True
         self.mock_gateway.return_value.delete_template.return_value.status_code = 204
-        self.mock_gateway.return_value.delete_template.return_value.headers = {'content-type': 'application/json'}
+        self.mock_gateway.return_value.delete_template.return_value.headers = {
+            'content-type': 'application/json; charset=utf-8'}
         self.command.config.parser_config(self.parser)
         changes = {
             (Change.added, './assets/base.html'),
@@ -357,7 +363,7 @@ def test_watch_command_with_create_image_file_should_call_gateway_with_correct_a
         self.command.config.parser_config(self.parser)
         self.mock_gateway.return_value.create_or_update_template.return_value.ok = True
         self.mock_gateway.return_value.create_or_update_template.return_value.headers = {
-            'content-type': 'application/json'}
+            'content-type': 'application/json; charset=utf-8'}
         changes = [
             (Change.added, './assets/image.jpg'),
         ]
@@ -381,7 +387,7 @@ def test_watch_command_with_sass_directory_should_call_compile_sass(
         ]
         self.mock_gateway.return_value.create_or_update_template.return_value.ok = True
         self.mock_gateway.return_value.create_or_update_template.return_value.headers = {
-            'content-type': 'application/json'}
+            'content-type': 'application/json; charset=utf-8'}
 
         changes = {
             (Change.modified, 'sass/theme.scss'),
diff --git a/tests/test_gateway.py b/tests/test_gateway.py
index 5ea866c..0165d24 100644
--- a/tests/test_gateway.py
+++ b/tests/test_gateway.py
@@ -100,7 +100,7 @@ def test_get_themes(self, mock_request):
         self.assertEqual(log.output, expected_logging)
 
         # check if call request completed
-        mock_request.return_value.headers = {'content-type': 'application/json'}
+        mock_request.return_value.headers = {'content-type': 'application/json; charset=utf-8'}
         self.gateway.get_themes()
 
         expected_call = call('GET', 'http://simple.com/api/admin/themes/',
@@ -124,7 +124,7 @@ def test_create_theme(self, mock_request):
 
         # check if call request completed
         mock_request.return_value.ok = True
-        mock_request.return_value.headers = {'content-type': 'application/json'}
+        mock_request.return_value.headers = {'content-type': 'application/json; charset=utf-8'}
         payload = {
             "name": "Test Init Theme"
         }
@@ -153,7 +153,7 @@ def test_get_templates(self, mock_request):
 
         # check if call request completed
         mock_request.return_value.ok = True
-        mock_request.return_value.headers = {'content-type': 'application/json'}
+        mock_request.return_value.headers = {'content-type': 'application/json; charset=utf-8'}
 
         self.gateway.get_templates(theme_id=6)
 
@@ -170,16 +170,18 @@ def test_get_template(self, mock_request):
         # check if call request failed
         with self.assertLogs(level='INFO') as log:
             mock_request.return_value.ok = False
+            mock_request.return_value.json.return_value = {
+                'detail': 'You do not have permission to perform this action.'}
             self.gateway.get_template(theme_id=6, template_name=template_name)
 
         expected_logging = [
-            'INFO:root:Downloading assets/custom.css file from theme id #6 failed.'
+            'INFO:root:Downloading assets/custom.css file from theme id #6 failed. -> You do not have permission to perform this action.' # noqa
         ]
         self.assertEqual(log.output, expected_logging)
 
         # check if call request completed
         mock_request.return_value.ok = True
-        mock_request.return_value.headers = {'content-type': 'application/json'}
+        mock_request.return_value.headers = {'content-type': 'application/json; charset=utf-8'}
 
         self.gateway.get_template(theme_id=6, template_name=template_name)
 
@@ -195,16 +197,19 @@ def test_create_or_update_template(self, mock_request):
         # check if call request failed
         with self.assertLogs(level='INFO') as log:
             mock_request.return_value.ok = False
+            mock_request.return_value.json.return_value = {
+                'detail': 'You do not have permission to perform this action.'}
             self.gateway.create_or_update_template(theme_id=6, template_name='asset/custom.css')
 
         expected_logging = [
-            'INFO:root:Uploading asset/custom.css file to theme id #6 failed.'
+            'INFO:root:Uploading asset/custom.css file to theme id #6 failed. -> You do not have permission to perform this action.' # noqa
         ]
+        print(log.output)
         self.assertEqual(log.output, expected_logging)
 
         # check if call request completed
         mock_request.return_value.ok = True
-        mock_request.return_value.headers = {'content-type': 'application/json'}
+        mock_request.return_value.headers = {'content-type': 'application/json; charset=utf-8'}
         payload = {
             'name': 'assets/base.html',
             'content': '{% load i18n %}\n\n<div class="mt-2">My home page</div>'
@@ -223,7 +228,7 @@ def test_create_or_update_template(self, mock_request):
     #####
     @patch('ntk.gateway.requests.request', autospec=True)
     def test_delete_template(self, mock_request):
-        mock_request.return_value.headers = {'content-type': 'application/json'}
+        mock_request.return_value.headers = {'content-type': 'application/json; charset=utf-8'}
         # check if call request failed
         with self.assertLogs(level='INFO') as log:
             mock_request.return_value.ok = False