When you set up your LDAP import at
Settings>User Authentication>Edit Mode>
Find the LDAP server and click the red clock on the right hand side.
As you step through the wizard you notice some users listed at the bottom that say they wont be imported becasue of errors.
Incomplete information in required fields
Notice in the filed mappings there are three fields that show in red text. (Ldap UID, USername, EMail)These are required fields by KACE and any user that is missing data in one of these fields fails the import requirement.
Make sure each user has the required data before scheduling the import.