LDAP Import users

hello, I recently installed request tracker 5.0.3 and I am trying to import and sync with Windows Server Active Directory users but I am having problems with this, the machine that has RT is already in the Domain but for some reason I am not able to import users of my Active Directory, my real settings are below with the Active Directory and the organizational unit to be imported and “Administrators” Who can help me and tell me what my mistake is, I already tried to put the ip of the Active Directory and also the name of the domain, but he doesn’t get there.