diff --git a/app/Listeners/Mail/MailSentListener.php b/app/Listeners/Mail/MailSentListener.php
index f2cbcd736b..daf79ac9e8 100644
--- a/app/Listeners/Mail/MailSentListener.php
+++ b/app/Listeners/Mail/MailSentListener.php
@@ -42,13 +42,16 @@ class MailSentListener implements ShouldQueue
      */
     public function handle(MessageSent $event)
     {
-        if(!Ninja::isHosted());
+        if(!Ninja::isHosted())
             return;
             
         $message_id = $event->sent->getMessageId();
 
         $message = MessageConverter::toEmail($event->sent->getOriginalMessage());
 
+        if(!$message->getHeaders()->get('x-invitation'))
+            return;
+
         $invitation_key = $message->getHeaders()->get('x-invitation')->getValue();
 
         if($message_id && $invitation_key)