The following ldapsearch command works, flawlessly.
ldapsearch -LLL -s sub -P 3 -D \"CN=,OU=IT,OU=Non-Users,OU=Users,OU=UserAccount,DC=,DC=com\" -H l
Here is my working AD settings for LDAP.
#########################################
ldap:
enabled: true
host: '16.184.18.88'
port: 636
uid: 'sAMAccountName' #userPrincipalName
method: 'ssl' # "tls" or "ssl" or "plain"
bind_dn: 'CN=Gitlab Git,CN=Users,DC=mydomain,DC=net'
password: 'My_Password'
allow_username_or_email_login: false
base: 'CN=Users,DC=mydomain,DC=net'
user_filter: '(memberOf=CN=Developers,OU=GitLabHQ,DC=mydomain,DC=net)'
group_base: 'OU=GitLabHQ,DC=mydomain,DC=net'
admin_group: GitLabAdmins
########################################