Facebook does not use article image
Having been through this before with OG tags and Facebook, if your site has been up and you verified the OG tags are in the source and work, then the likely culprit is that Facebooks crawler cached the page before you added the tag and you will need to wait a while.

If the image url resolves and the tag is right, it just takes time.

Perhaps try to look into using the Facebook debugger, something like in this article: https://www.braveriver.com/how-to-clear-facebook-open-graph-and-twitter-cards-cache-on-demand/

We saw this behavior with both Facebook and Twitter. IIRC it took about 3-6 hours to see them "appear" after initial attempts.