Fix Facebook Invalidated Session Error in Revive Old Posts
If you receive the error:
Unable to share post for facebook. (FacebookResponseException) Error: Error validating access token: The session has been invalidated because the user changed their password or Facebook has changed the session for security reasons.
Then this means that you recently changed your Facebook password or your session has for some reason be reset by Facebook. The solution here is to simply reconnect your Facebook account to the Revive Old Posts plugin and restart the sharing.