You'll get this issue upon debugging the page with Facebook sharing debugger here: https://developers.facebook.com/tools/debug/ - with the error message of 'the following required properties are missing: fb:app_id' To fix:
- Inspect element to check whether the meta property for fbapp_id is exist on your site. If not, add the following code to your site header.
-
<meta property="fb:app_id" content="ХХХХХХХХХХХХХХХ" />
- Get the fb id from here: https://developers.facebook.com/apps/ .example as follows:

- and replace the content="ХХХХХХХХХХХХХХХ" value with your fb ids