Post Thumbs not showing up on Single Post

I’m trying to get a post thumbnail to show up in the meta for Facebook. For some reason wordpress is not acknowledging that a post thumb even exists on the single post page but works on the index.php/main loop just fine. I’ve used the code below on other WP sites, but it is not working here.

<meta property="og:image" content="<?php $image_id = get_post_thumbnail_id();
$image_url = wp_get_attachment_image_src($image_id,'large');
$image_url = $image_url[0]; ?>"/>

I’ve also used the same the post thumb declaration as on the homepage to no avail. I was hoping someone had some insight as to why WordPress isn’t recognizing my post thumbs on a single post page.

Main: https://blog.fethastyx.com/
Single Post: https://blog.fethastyx.com/2011/04/redfish-fishing-report-with-chris-williams-lafitte-la/