diff --git a/osa4.md b/osa4.md
index 8ec3b4c..a9901de 100644
--- a/osa4.md
+++ b/osa4.md
@@ -2254,7 +2254,7 @@ loginRouter.post('/', async (request, response) => {
     await bcrypt.compare(body.password, user.passwordHash)
 
   if ( !(user && passwordCorrect) ) {
-    return response.status(401).send({ error: 'invalid username or password' })
+    return response.status(401).json({ error: 'invalid username or password' })
   }
 
   const userForToken = {