The Facebook integration only works with pages. It will not work with Facebook groups or accounts.
Also, groups.io has no way to log into Facebook to see your page content. Your page must be visible to everybody, without logging in.
If you get the error "That name does not appear to be the name of a Facebook page," check the Facebook page settings. The page must be published, it must be public, and it must have NO age or country restrictions.
See also: https://boostlikes.com/blog/2017/04/fix-page-visible-public
Last updated: 04Jan2019