Serialization of 'Closure' is not allowed in Laravel 5.3 Email Queue

You cannot serialize request. Only eloquent model can be serialized and unserialzed. See here: https://laravel.com/docs/5.2/queues#writing-job-classes

You should use $request->all() instead of $request. Since Request is treated as closure.

Try removing this line from constructor:

$this->message = new Message();

and, in the handle directly initialise it.

$student = $this->data;
$arrStudent = (new Message())->getEmailAddressList($student);
Mail::to($arrStudent)->send(new MessageSent($student));