iron.io queue system sends emails infinitely

I'm using Laravel 5.1 and the iron.io version 4 , I use the queue to send emails and also I configured a supervisor to avoid typing php artisan queue:listen now the problem is in the log file (storage/logs) I get an error message

 [IronCore\HttpException]                                  
  http error: 400 | {"msg":"A reservation_id is required"}  

and the email get sended infinitely every minute , what to do to stop sending emails ? please I need your help guys

via Chebli Mohamed