PHP error but no error code shown.

<?php
        $app -> post('/about', function() use($app){
           $name = $app->request->post('user_name');
           $email = $app->request->post('user_email');
           $job = $app->request->post('user_job');
           $msg = $app->request->post('user_text');

    if(!empty($name) && !empty($email) && !empty($job) && !empty($msg)){
        $cleanName = filter_var($name, FILTER_SANITIZE_STRING);
        $cleanEmail = filter_var($email, FILTER_SANITIZE_EMAIL);
        //$cleanJob = filter_var($job, FILTER_SANITIZE_STRING);
        $cleanMsg = filter_var($msg, FILTER_SANITIZE_STRING);
    } else {
        //error
        $app->redirect('/');
    }

    $transport = Swift_SendmailTransport::newInstance('/usr/sbin/sendmail -bs');
    $mailer = \Swift_Mailer::newInstance($transport);

    $message = \Swift_Message::newInstance();
    $message -> setSubject('Email from website');
    $message -> setFrom(array(
         $cleanEmail => $cleanName
    ));
    $message -> setTo(array('MyOfficalEmailAddressisHere'));
    $message -> setBody($cleanMsg);

    $result = $mailer -> send($message);

    if($result>0){
        $app->redirect('/');
    } else {
        // Message fails to send
        $app->redirect('/');
    }


});

$app -> run();

?>