@morrow without logs this will be hard to track down. can you ask your administrator to open up a support case for this?
To integrate Zarafa with an Active Directory server, you need to specify the LDAP search queries in the ldap.cfg file. From these search queries, Zarafa can locate the users and groups in the ADS.
To ensure the LDAP search queries are as fast as possible, we advise you to specify a subfolder in the LDAP structure, where all users are located. By specifying the subfolder in the ADS, the LDAP search does not need to search the complete tree.
By default, Zarafa generates an Outlook store for every found user in the LDAP tree. When users in the ADS do not use Zarafa, you should put them in a separate folder in the ADS, where Zarafa does not search for users.
To specify groups for Zarafa, we advise you to create a separate folder in the LDAP tree and create all the Zarafa groups in this folder. By creating a specific folder for groups, not all the Windows system groups are visible in Zarafa.
An example ADS configuration file is found in /usr/share/zarafa/ads.cfg. This file can be used as a template for ADS servers.
Read more about Active Directory integration in the Zarafa LDAP whitepaper.