The way Facebook Business apps request their permissions has changed. I just posted a beta test version of the Facebook Business Provider plugin which should fix this for Pages. (I'll have to investigate whether groups is still allowed). You can find the build in your My Account > My Subscriptions area.
You'll have to
* Install the plugin
* Go into your Facebook business app and set up a Configuration (found under Facebook Business Login). The permissions you request should be email, pages_manage_posts, pages_read_engagement, pages_read_user_content and pages_show_list.
* Copy the configuration id to JFBConnects new corresponding setting in the Facebook Business provider. (*The language key is not added yet since it's included in the JFBConnect package)
The redirect URI needs to be updated for Twitter (I am in the process of updating the app setup guide). It needs to be in the following format now:
https://yoursite.com/index.php?option=com_jfbconnect&task=authenticate.callback&provider=twitter
Also, please post from the account with your subscription to JFBConnect. Priority support is for active subscribers only.