LDAP keeps returning empty

Hi,
I’m trying to get users from Active Directory using LDAP. when I ran ldapsearch from command line I get a list of users for this command:
ldapsearch -D "cn=ldapsearch AUTO, OU=Corp Users,dc=Corp,dc=Local" -w password -p 389 -h 192.168.1.100 -b "ou=Corp Users,dc=Corp,dc=Local"

when I get zero results when I use gitlab.rb like this:

gitlab_rails['ldap_enabled'] = true
gitlab_rails['ldap_servers'] = YAML.load <<-EOS # remember to close this block with 'EOS' below
 main:
  label: 'ActiveDirectory'
  host: '192.168.1.100'
  port: 389 #Change to 636 if using LDAPS
  encryption: 'plain' # Change to "tls" if using LDAPS
  uid: 'sAMAccountName' # Don't change this
  lowercase_usernames: true
  bind_dn: 'cn=ldapsearch AUTO,OU=Corp Users,dc=Corp,dc=Local'
  password: 'password'
  timeout: 10
  active_directory: true
  allow_username_or_email_login: true
  block_auto_created_users: false
  base: 'dc=Corp,dc=Local'
  #Optional: the next line specifies that only members of the user group "gitlab-users" can authenticate to Gitlab:
  #user_filter: '(memberOf:1.2.840.113556.1.4.1941:=CN=GITLAB-USERS,CN=Users,DC=CORP,DC=COM)'
  user_filter: ''
  attributes:
    name:       'displayName'
    first_name: 'givenName'
    last_name:  'sn'

EOS

The actual result I get is this:

Checking LDAP …

LDAP: ... Server: ldapmain
LDAP authentication... Success
LDAP users with access to your GitLab server (only showing the first 100 results)

Checking LDAP ... Finished