diff --git a/deploy-board/deploy_board/webapp/error_views.py b/deploy-board/deploy_board/webapp/error_views.py
index 01756e343e..2438d98e00 100644
--- a/deploy-board/deploy_board/webapp/error_views.py
+++ b/deploy-board/deploy_board/webapp/error_views.py
@@ -41,7 +41,9 @@ def process_exception(self, request, exception):
         if request.is_ajax():
             ajax_vars = {'success': False, 'error': str(exception)}
             ret = 500
-            if isinstance(exception, FailedAuthenticationException):
+            if isinstance(exception, IllegalArgumentException):
+                ret = 400
+            elif isinstance(exception, FailedAuthenticationException):
                 ret = 401
             elif isinstance(exception, NotAuthorizedException):
                 ret = 403