Artica perform an LDAP query to the Active Directory server. The Active Directory server limit one query to 1500 entries.
You have 2 ways to allow Artica browsing the users in Active Directory
- Create multiple groups that did not exceed 1500 users.
- Increase the MaxValRange on your Active Directory to the number of users stored in the Active Directory Group.
see https://support.microsoft.com/en-us/kb/315071