shell bypass 403
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" <?php language_attributes(); ?>>
<head>
<meta http-equiv="Content-type" content="text/html; charset=utf-8"/>
<meta http-equiv="Imagetoolbar" content="No"/>
<meta name="viewport" content="width=device-width, initial-scale=1">
<title><?php esc_html_e('Preview Form', 'fluentform') ?></title>
<?php
wp_head();
?>
</head>
<body>
<div id="preview_top">
<?php echo do_shortcode('[fluentform id="142"]'); ?>
</div>
<?php
wp_footer();
?>
</body>
</html>