Here is a checklist of items to check:
On the MS Exchange V5.5, LDAP configuraiton:
1. LDAP (Directory) Settings – Make sure Windows NT Challenge/Response is checked
2. Do not use Anonymous access because the anonymous user will not be able to access the properties of each users. Use a user with administrative privileges
3. Check the “Maximum number of search results returned” default value. If necessary Increase from 100 to 200 if there is there is an error message returned on number of searched reached.
On the K1000 appliance:
1. Using the LDAP browser, check if the user properties exist a samaccountname variable or not. If it doesn't exist, check if the properties is using UID instead. In the kbox server, use (UID=kBOX_USER) instead of .(samaccountname=KBOX_USER)
2. When entering the LDAP user for access, use the following syntax in the Kbox side: