Gilab EE Active Directory Group synchronization

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1

I have successfully integrated our active directory server with Gitlab Enterprise. What i struggling with is enabling ldap synchronization for group permissions.
When i create a group and go into the group’s settings, i dont see the LDAP synchronization option.

Here is the configurations i am currently using

gitlab_rails['ldap_enabled'] = true
gitlab_rails['ldap_servers'] = {
'main' => {
  'label' => 'TEST AD',
  'host' =>  '192.16.2.34',
  'port' => 3268,
  'uid' => 'sAMAccountName',
  'encryption' => 'plain',  #
  'verify_certificates' => false,
  'bind_dn' => 'CN=ldaptest,OU=Service Accounts,OU=User Accounts,DC=prod,DC=example,DC=com',
  'password' => 'mypassword',
  'active_directory' => true,
  'base' => 'DC=prod,DC=example,DC=com',
  'group_base' => 'OU=Ldaptest,OU=Groups,DC=prod,DC=example,DC=com',
  'admin_group' => 'my-admin',
  'user1_group' => 'user1-group',
  'user2_group' => 'user2-group'
  }
}