Feature Image of all posts not showing on external links

I have taken over a WordPress site From someone else and finding that the feature image of all the posts are not showing in any external links to it. I use Elementor. I tried switching from Yoast SEO to All In One SEO using correct settings to enable Open Graph Markup etc. I have disabled plugins and tried all sorts of possible solutions, but the missing feature image remains a mysterious problem. I run other WordPress sites, but none have this issue.

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