Facebook Graph API 2.12 came with another huge functionality killing announcement.
Facebook disabled the ability to post to “Public” groups where you just a member in Graph API 2.12 with 90 Days depreciation delay for earlier API versions.
It means that if you made a Facebook App after January 30, 2018, you won’t be able to post to “Public” groups where you just a member. If you made an app before January 30, 2018 you will loose that ability around May 1st, 2018
Facebook is saying “You made an app after January 30, 2018 and you won’t be able to post to “Public” groups” in from of “(#200) The user has not authorized the application to perform this action.” error.
PS: This is really a huge change to official Facebook API. It removes a very popular feature from SNAP. We are considering creating our own API for Facebook that won’t have such limitations.