diff --git a/pagure/api/__init__.py b/pagure/api/__init__.py
index 0e8910a..353c8c8 100644
--- a/pagure/api/__init__.py
+++ b/pagure/api/__init__.py
@@ -28,6 +28,7 @@ API_ERROR_CODE = {
     2: 'No issue tracker found for this project',
     3: 'An error occured at the database level and prevent the action from '
         'reaching completion',
+    4: 'Invalid or incomplete input submited',
 }