diff --git a/hw6/Claudio_Maggioni/routes/utils.js b/hw6/Claudio_Maggioni/routes/utils.js
index 215c1d7..0225b51 100644
--- a/hw6/Claudio_Maggioni/routes/utils.js
+++ b/hw6/Claudio_Maggioni/routes/utils.js
@@ -8,7 +8,8 @@ function catchErrs(promise, res) {
 
 function error(err, res) {
   console.error(err);
-  res.status = 500;
+  res.status = err instanceof mongoose.CastError ||
+    err instanceof mongoose.TypeError ? 400 : 500;
   res.format({
     json: () => res.json({ error: err }),
     html: () => res.render('500.dust', { err: JSON.stringify(err, null, 2) }),