Hi there!

My setup:
Samba 4 for AD functionality and Zimbra for e-mail and collaboration.
So far, so good. Defined external source for authentication and everything goes perfect... but...
authentication just stop working randomly one or two times a week.
audit.log writes:
" security - cmd=Auth; account=info@domain.com; protocol=pop3; error=authentication failed for [info@domain.com], missing userPassword;"
Samba 4 server is up and running, reachable from mail server (ping, ssh), network shares are working, besides samba retrieves no error messages.
Restarting samba 4 temporary fixes the problem. But i would like to find out why does it happens and how to fix that!