This has nothing to do with Facebook’s API change or developer account.
Instead, you changed your site’s permalinks from /year/month/day/postname/ to just /postname/ — so all the links shared on Facebook and elsewhere before the change are broken.
When you change permalink format like that, you should add a 301 redirect rule in .htaccess that matches the old format with an appropriate regexp, and if there’s a match, do the 301 redirect to the proper new URL. A regexp matching scheme like this does require that the postname remains unchanged from old to new. The regexp matches the dropped year/month/date portion and captures the postname part for use in constructing the proper, new permalink that’s redirected to.
I had no idea. But I changed it back and now it works!! 🙂
Thank you so much to both of you!
