diff --git a/lib/src/exception.dart b/lib/src/exception.dart
index 3f33f4c8..3e140784 100644
--- a/lib/src/exception.dart
+++ b/lib/src/exception.dart
@@ -7,7 +7,7 @@ class AuthorizationException extends AngelHttpException {
   AuthorizationException(this.errorResponse,
       {StackTrace stackTrace, int statusCode, error})
       : super(error ?? errorResponse,
-            stackTrace: stackTrace, message: '', statusCode: statusCode ?? 401);
+            stackTrace: stackTrace, message: '', statusCode: statusCode ?? 400);
 
   @override
   Map toJson() {
diff --git a/lib/src/server.dart b/lib/src/server.dart
index d42883c8..07ec42a5 100644
--- a/lib/src/server.dart
+++ b/lib/src/server.dart
@@ -66,7 +66,7 @@ abstract class AuthorizationServer<Client, User> {
         'Authorization code grants are not supported.',
         state,
       ),
-      statusCode: 405,
+      statusCode: 400,
     );
   }
 
@@ -87,7 +87,7 @@ abstract class AuthorizationServer<Client, User> {
         'Authorization code grants are not supported.',
         state,
       ),
-      statusCode: 405,
+      statusCode: 400,
     );
   }
 
@@ -103,7 +103,7 @@ abstract class AuthorizationServer<Client, User> {
         'Authorization code grants are not supported.',
         req.query['state'] ?? '',
       ),
-      statusCode: 405,
+      statusCode: 400,
     );
   }
 
@@ -120,7 +120,7 @@ abstract class AuthorizationServer<Client, User> {
         'Refreshing authorization tokens is not supported.',
         req.body['state'] ?? '',
       ),
-      statusCode: 405,
+      statusCode: 400,
     );
   }
 
@@ -138,7 +138,7 @@ abstract class AuthorizationServer<Client, User> {
         'Resource owner password credentials grants are not supported.',
         req.body['state'] ?? '',
       ),
-      statusCode: 405,
+      statusCode: 400,
     );
   }
 
@@ -151,7 +151,7 @@ abstract class AuthorizationServer<Client, User> {
         'Client credentials grants are not supported.',
         req.body['state'] ?? '',
       ),
-      statusCode: 405,
+      statusCode: 400,
     );
   }
 
@@ -319,7 +319,7 @@ abstract class AuthorizationServer<Client, User> {
                 'Invalid "client_id" parameter.',
                 state,
               ),
-              statusCode: 401,
+              statusCode: 400,
             );
           }
 
@@ -330,7 +330,7 @@ abstract class AuthorizationServer<Client, User> {
                 'Invalid "client_secret" parameter.',
                 state,
               ),
-              statusCode: 401,
+              statusCode: 400,
             );
           }
         }
diff --git a/pubspec.yaml b/pubspec.yaml
index cd10ecde..75ae825a 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -2,7 +2,7 @@ name: angel_oauth2
 author: Tobe O <thosakwe@gmail.com>
 description: angel_auth strategy for in-house OAuth2 login.
 homepage: https://github.com/thosakwe/oauth2_server.git
-version: 1.0.0-alpha
+version: 1.0.0-alpha+1
 environment:
   sdk: ">=1.19.0"
 dependencies: 
diff --git a/test/client_credentials_test.dart b/test/client_credentials_test.dart
index 06c074b6..22fa6042 100644
--- a/test/client_credentials_test.dart
+++ b/test/client_credentials_test.dart
@@ -65,7 +65,7 @@ main() {
     );
 
     print('Response: ${response.body}');
-    expect(response, hasStatus(401));
+    expect(response, hasStatus(400));
   });
 
   test('force correct secret', () async {
@@ -80,7 +80,7 @@ main() {
     );
 
     print('Response: ${response.body}');
-    expect(response, hasStatus(401));
+    expect(response, hasStatus(400));
   });
 }