Hi. It's not necessary to create any user account in OsTicket before :)Account is automatically created at the first logon (only if the user exists in A.D)Fill out Domain Name field with FQDN Domain Name (example : athome I have a domain named : msad.athome.com with short name ATHOME. So i typed msad.athome.com)In DNS Server, type your DNS IP Address (if the Domain controler hosts the DNS service, type the domain controller IP)and give at leat 1 Domain Controler IP (classically, ping your FQDN domain name, and enter the provided IP)In LDAP Type (or LDAP Schema) field, choose Microsoft Active Directory, and save your changes.It should works fine. In my organization, users are referenced in different UO, and there is no problem with authentication. Just an advice - this is our process to prevent from including unuseful data in reportings : create local users for agents (agent login must not be configured to authenticate with LDAP) - So they can use separately end user UI and admin UI at the same time.Don't hesitate to tell me if it has help you :)(And sorry for my english)