nss_ldap: failed to bind to LDAP ser

[Gokan Atmaca <linux.gokan@gmail.com>]

I installed OpenLDAP. "ldapsearch -x" comes with everything. However,
I get an error when I try to connect to the client as follows:

Ldapcliet: (/var/log/auth.log)

02:49:58 debian8 nscd: nss_ldap: reconnecting to LDAP server (sleeping
1 seconds)...
May 31 02:49:59 debian8 nscd: nss_ldap: could not connect to any LDAP
server as (null) - Can't contact LDAP server
May 31 02:49:59 debian8 nscd: nss_ldap: failed to bind to LDAP server
ldapi://ldap01.gokan.local: Can't contact LDAP server
May 31 02:49:59 debian8 nscd: nss_ldap: could not search LDAP server -
Server is unavailable

======================
Ldapserver;

# ldapsearch -x

# extended LDIF
#
# LDAPv3
# base <dc=gokan,dc=local> (default) with scope subtree
# filter: (objectclass=*)
# requesting: ALL
#

# gokan.local
dn: dc=gokan,dc=local
objectClass: top
objectClass: dcObject
objectClass: organization
o: gokan
dc: gokan

# admin, gokan.local
dn: cn=admin,dc=gokan,dc=local
objectClass: simpleSecurityObject
objectClass: organizationalRole
cn: admin
description: LDAP administrator

# IT, gokan.local
dn: ou=IT,dc=gokan,dc=local
objectClass: organizationalUnit
objectClass: top
ou: IT

# Genel, IT, gokan.local
dn: cn=Genel,ou=IT,dc=gokan,dc=local
gidNumber: 500
cn: Genel
objectClass: posixGroup
objectClass: top

# Gokhan Atmaca, Genel, IT, gokan.local
dn: cn=Gokhan Atmaca,cn=Genel,ou=IT,dc=gokan,dc=local
cn: Gokhan Atmaca
givenName: Gokhan
gidNumber: 500
homeDirectory: /home/users/gokhana
sn: Atmaca
loginShell: /bin/sh
objectClass: inetOrgPerson
objectClass: posixAccount
objectClass: top
uidNumber: 1000
uid: gokhana


# search result
search: 2
result: 0 Success

# numResponses: 7
# numEntries: 6

======================

Listening to the socket.
tcp        0      0 0.0.0.0:389             0.0.0.0:*
LISTEN      4409/slapd
tcp6       0      0 :::389                  :::*
LISTEN      4409/slapd


What could be the problem?