1. Verify that you can access the LDAP using Softerra LDAP Browser
2. Verify that you selected the correct OUs in source/target in the CMN/DC connector.
3. Verify that the migration account has enough Domino permissions.
4. Enable LDAP Debugging on the Domino Console to trace the LDAP conversations
5. Check the setting for the LDAP timeout from Domino Admin (server configuration).
if needed, increase it or reset it to "0" (unlimited).