Setup of the facebook auto posting does not work when following your guide due to facebook app changes.
Per this article: In march 2018 facebook has updated their app Auth URI's to be specific, and this CANNOT BE TURNED OFF, your guide sayds to use the sites URL (which is not the specific URI and wont work.) Also as a side note you should add to your doc that all URLS must be HTTPS.
See this article for full details:
https://wp-native-articles.com/blog/news/how-to-fix-facebook-apps-error-cant-load-url-domain-url-isnt-included-apps-domains/
As such Your guide on setting up the app for facebook integration needs to be urgently updated as it does not work anymore.
Please can you advise me on the strict URI URL i am supposed to use for easyblog to link to an app. Thanks.