ldapsearch -x -Z -H ldap://<IP>:389 -D "AD Admin DN" -W -b "users/admin Search context"
Examples:
ldapsearch -x -Z -H ldap://xxx.xxx.xxx.xxx:389 -D "CN=Administrator, cn=Users, dc=xyz,dc=com" -W -b " cn=Users, dc=xyz,dc=com"
or if you have configured certificate as mentioned previously attached document and AD is running in SSL mode you can try,
ldapsearch -x -Z -H ldaps://xxx.xxx.xxx.xxx:636 -D "CN=Administrator, cn=Users, dc=xyz,dc=com" -W -b " cn=Users, dc=xyz,dc=com"