diff --git a/physics/views.py b/physics/views.py
index 5ef506f4..41158f74 100644
--- a/physics/views.py
+++ b/physics/views.py
@@ -267,7 +267,7 @@ def loadJsonAnswer(answer):
     # The model should catch invalid data but this should be less intensive
     max_int = 2147483647
     if answer["cid"] > max_int or answer["eid"] > max_int:
-        return False, JsonResponse({"success": False})
+        return False, JsonResponse({"success": False, "error": "invalid candidate id"})
 
     exam = get_object_or_404(Exam, pk=answer["eid"])