I also am receiving the following message on the debug page:
“fb:app_id hasn’t been included in the meta tags. Specify the app ID so that stories shared to Facebook will be properly attributed to the app. Alternatively, app_id can be set in url when open the share dialog. Otherwise, the default app id( 966242223397117 ) will be assigned”
I finally managed to avoid the “generic head” icon that suddenly started appearing while sharing my WordPress blog post on Facebook by manually selecting a photo in the Social Settings tab of the AIOSEO section of the post page.
Thanks to the AIO SEO team for creating such a helpful and powerful plugin!
https://www.elcanche.com