So, I got this software few weeks ago. I've tried everything including the new download 6.5 today. I experience exactly the same issue like the other guy, I can see the auto post, but none else can't, including other page admins. The trick with putting on/off the "Development Mode" of Facebook works, but of course this can't happen and it's not automated.
I've tried everything and I considered myself very experienced on this, since I'm using the K2 ->Facebook for many years (which is also not working anymore).
It's obvious that something has changed from facebook part, or the app is dead?