Nope... firewall has been off since day 1. The only thing that is running is Little Snitch but even turning this off causes a fail upon trying to reach the address. Again - local IP load calibre server just fine... its only when I try outside IP (from inside OR outside) that it fails on MAC only.
Might just need to shift this whole thing over to my windows machine and just have it running 24/7 to host the books... silly since my MAC is already on 24/7 but I just can't figure this out and frankly.. I'm getting tired of trying.