I pulled out my hair trying to solve this problem. The hours and hours of troubleshooting are inconclusive. After talking with one of our programmers about an unrelated topic, I thought about something to try and take a long shot.
To my surprise, it worked !!!
This is the cause of the problem and my solution for it is:
When you create a post in WordPress, it creates a link based on the title of your article (unless you manually modify it). The heading of my article included special characters, however the automatically generated link did not display these special characters, but only hyphens to replace spaces. Should it be good? Wrong! Somewhere, embedded in the metadata and code on the WordPress platform are these special characters, and they messed up the way Facebook retrieves information from a related article. This is a problem because some special characters invalidate hyperlinks.
For instance:
Article Title: R [eloaded]
Auto-generated DISPLAYED hyperlink in the "Permalink" WordPress field: http://www.example.com/reloaded
Actual WordPress Auto-Generated Hyperlink: http://www.example.com/r [eloaded]
These brackets invalidate the link, and Facebook will not be able to extract any information from it (i.e. images).
Decision:
(1) Just manually change the WordPress hyperlink address to something that does not contain any special characters (this will not change the name of your article).
(2) Click Refresh to edit the message to include the new hyperlink.
(3) Click "Clear Cache" in WordPress Window
(4) Refresh your Facebook browser window.
(5) Insert a new hyperlink for your article
(6) Enjoy your Facebook post with preview and information.
Sidenote: Don’t pull your hair over Facebook, it’s not worth it. =)