I have encountered this same situation on my Jessie samba4 server. The one additional bit of information I have to offer is that connects from my Windows 8.1 client die immediately when they are attempted (as described by Lorin), but connects from my Windows 7 client seem to be unaffected.
Thanks, Scott Bailey sc...@cartasoft.com -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org