If you are using your own app then please upgrade api version to v7.0 at Facebook developer settings of your app(under Advanced settings).
If your app is reviewed and approved for the permission publish_pages and manage_pages then the permissions will be automatically migrated to the new permissions as per the new Facebook API changes.also your site must have SSL certificate for connecting to Facebook.
For removing the app from Facebook,go to
https://www.facebook.com/settings?tab=business_tools
From the connected apps ,remove the app you are using in plugin.
If you are using smapsolutions app then remove ‘SMAP Lite’.
If you are using your own app then remove it .
Then try to reauthorize by clicking on the Authorization Button.
If there is any permission issues you can use smapsolutions app free for 1 month.
And submit your app for review, we have updated the documentation for app review in 7.0 version of Facebook Graph API at
https://help.xyzscripts.com/docs/social-media-auto-publish/faq/how-can-i-create-facebook-application/
Hope this helps.
Thank you.