In user manager, you select Import and then LOAD for a specific LDAP server and get "Error while receiving LDAP Server User List from Domain Server Connection".
This error is typically caused by the list of users being returned from LDAP being too large. You can control the size of the list using the filter settings in node.properties for the Domain Server.
server.domain.ldap.<ldapserver1>.user.filter = <LDAP user filter>
server.domain.ldap.<ldapserver1>.group.filter = <LDAP group filter>
These options will limit the search to a specific set of users and/or groups.
We suggest using Automatic creation for LDAP users to eliminate the need to manually add them at all.
For additional information, see Configuring Domain Server for LDAP in the Administrator's Guide
For additional troubleshooting information, review How to troubleshoot Domain Server LDAP Security Integration