php icon is not visible

I reinstalled several times ad-inserter on my website, but the php insert icon is not visible, on other my sites hosted on the same server it is visible. He disabled the Caché plugins as well as the rest of the plugins, but the php icon still does not come out. When you inserted the code, for example: <?php get_related_posts_thumbnails(); ?> is also not visible. See captures the difference between two sites.

<a href="https://imgur.com/vgTh0sZ"><img src="https://i.imgur.com/vgTh0sZ.png" title="source: imgur.com" /></a>

The page I need help with: [log in to see the link]