I have seen this twice in the last 2 days...
Running ZCS 4.5.4, with connector for 4.5.4.
Running External LDAP Auth
Running Samba Domain for Windows Users Auth from same LDAP
Samba requires password change every 90 days
When I change my LDAP password, Outlook hangs on open. I would expect that Zimbra would request a new password if auth fails, but it does not seem to.
Uninstall and reinstall of Zimbra connector fixes the problem, but it would be annoying to have all of my users do that every time the password changes.