og image missing

I use WPSSO for a long time.
Today I wrote 3 posts with no issues. They are simple: a photo with tiny text.
With the fourth Facebook preview lacks the image even I tried to set a Featured image (the same as the post)
Facebook Scrap again displays the default image site, not the post one.
“The ‘og:image’ property should be explicitly provided, even if a value can be inferred from other tags.”
Also the list of posts shows the others with an image in the “SSO image” column but this one (I also found another old one with the same problem I didn’t realize until now)
Thank you

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