diff --git a/app/Http/Controllers/InvoiceController.php b/app/Http/Controllers/InvoiceController.php
index 26c7d722..08216b98 100644
--- a/app/Http/Controllers/InvoiceController.php
+++ b/app/Http/Controllers/InvoiceController.php
@@ -355,7 +355,9 @@ class InvoiceController extends Controller
                 $message->to('uldvstar@gmail.com');
                 $message->subject('DO for booking no'.$booking->id);
                 //Attach PDF doc
-                $message->attachData($do->Output(),'do_booking_no_'.$booking->id.'.pdf');
+                $message->attachData($do->Output(),'do_booking_no_'.$booking->id.'.pdf', [
+                    'mime' => 'application/pdf',
+                ]);
             });
 
             if(!$booking) {