Just a quick note for those users of this who are seeking to embed Facebook content:
Facebook content must be publicly viewable. You cannot embed links to content inside private groups or content a user has set privacy to not be public on, it will return an error. The plugin lacks your credentials to access the material.
If you had to fill out a questionnaire or apply to join a group, most likely it is private.
Unfortunately there is nothing we can do about this, it is how Facebook itself is setup.
Ave Atque Vale