diff --git a/app/Http/Controllers/PreviewController.php b/app/Http/Controllers/PreviewController.php
index 8afcb713d3..57d1d17529 100644
--- a/app/Http/Controllers/PreviewController.php
+++ b/app/Http/Controllers/PreviewController.php
@@ -266,7 +266,7 @@ class PreviewController extends BaseController
 
 
         $response = Response::make($file_path, 200);
-        $response->header('Content-Type', 'application/pdf');
+        $response->headers->set('Content-Type', 'application/pdf');
 
         return $response;