When you drop a website post link into Facebook does it populate with the post title and featured image, like you’d expect?
While there could be many reasons behind this, one possible solution could be as simple as your DNS settings.
Facebook scrapes a preview of website posts based on the AAAA DNS record (IPv6). If you’ve got one of those set for your site – make sure it points to the same server address as your A record and IPv4 address.
In the instance that had us against the ropes for a time, it all dawned on me when I saw an AAAA record in the DNS after moving the NS from one provider to another.
The A record pointed to the new server, the AAAA to the old server. Facebook was looking for content on an old server where the post didn’t exist. That’s why we were getting a 404 error when every other check was fine.
To test, I deleted the AAAA record. Poof, the Facebook debug tools started delivering the post results as expected.