The AD Connector stops syncing and in the
/var/log/univention/connector.log you see entries like this:
26.01.2017 09:44:37,730 LDAP (ERROR ): Traceback (most recent call last): File "/usr/lib/pymodules/python2.7/univention/connector/__init__.py", line 1326, in sync_to_ucs f(self, property_type, object) File "/usr/lib/pymodules/python2.7/univention/connector/ad/password.py", line 381, in password_sync res = get_password_from_ad(connector, univention.connector.ad.compatible_modstring(object['dn'])) File "/usr/lib/pymodules/python2.7/univention/connector/ad/password.py", line 180, in get_password_from_ad (level, ctr) = connector.drs.DsGetNCChanges(connector.drsuapi_handle, 8, req8) NTSTATUSError: (-1073741300, 'The transport connection is now disconnected.')
This is currently a known bug. The ad-connector does not restart automatically once the connection got dropped.
Just restart the ad-connector by
systemctl restart univention-ad-connector
After a restart of the ad-connector it is running fine again.