LDAP config not working in grafana 5.2.1

Hi,
I am setting up Grafana 5.2.1 in my lab to use as backed for Elasticsearch datasource.

But I am facing issue in configuring LDAP authentication. I have configured ldap with default setting but getting belwo error:

t=2018-07-24T09:01:17-0700 lvl=eror msg=“Invalid username or password” logger=context userId=0 orgId=0 uname= error=“Invalid Username or Password”
t=2018-07-24T09:01:17-0700 lvl=info msg=“Request Completed” logger=context userId=0 orgId=0 uname= method=POST path=/login status=401 remote_addr=10.115.248.139 time_ms=40 size=42 referer=http://lXXXXXXXXX:3000/login

Below is my ldap config:
verbose_logging = true

[[servers]]
host = “abc.xyz.com
port = 636
use_ssl = true
start_tls = false
ssl_skip_verify = true

root_ca_cert = “/path/to/certificate.crt”

bind_dn = “cn=%s,ou=XXX,ou=XXX,dc=XXX,dc=xyz,dc=com”
search_filter = “(sAMAccountName=%s)”
search_base_dns = [“dc=XXX,dc=XYZ,dc=com”]

In POSIX LDAP schemas, without memberOf attribute a secondary query must be made for groups.

This is done by enabling group_search_filter below. You must also set member_of= “cn”

in [servers.attributes] below.

Users with nested/recursive group membership and an LDAP server that supports LDAP_MATCHING_RULE_IN_CHAIN

can set group_search_filter, group_search_filter_user_attribute, group_search_base_dns and member_of

below in such a way that the user’s recursive group membership is considered.

Nested Groups + Active Directory (AD) Example:

AD groups store the Distinguished Names (DNs) of members, so your filter must

recursively search your groups for the authenticating user’s DN. For example:

group_search_filter = “(member:1.2.840.113556.1.4.1941:=%s)”

group_search_filter_user_attribute = “distinguishedName”

group_search_base_dns = [“ou=groups,dc=grafana,dc=org”]

[servers.attributes]

member_of = “distinguishedName”

Group search filter, to retrieve the groups of which the user is a member (only set if memberOf attribute is not available)

group_search_filter = “(&(objectClass=posixGroup)(memberUid=%s))”

Group search filter user attribute defines what user attribute gets substituted for %s in group_search_filter.

Defaults to the value of username in [server.attributes]

Valid options are any of your values in [servers.attributes]

If you are using nested groups you probably want to set this and member_of in

[servers.attributes] to “distinguishedName”

group_search_filter_user_attribute = “distinguishedName”

An array of the base DNs to search through for groups. Typically uses ou=groups

group_search_base_dns = [“ou=groups,dc=grafana,dc=org”]

Specify names of the ldap attributes your ldap uses

[servers.attributes]
name = “givenName”
surname = “sn”
username = “cn”
member_of = “memberOf”
email = “email”

Map ldap groups to grafana org roles

[[servers.group_mappings]]
group_dn = “cn=admins,dc=grafana,dc=org”
org_role = “Admin”

The Grafana organization database id, optional, if left out the default org (id 1) will be used

org_id = 1

[[servers.group_mappings]]
group_dn = “cn=users,dc=grafana,dc=org”
org_role = “Editor”

[[servers.group_mappings]]

If you want to match all (or no ldap groups) then you can use wildcard

group_dn = “*”
org_role = “Viewer”

LDAP config in grafana.ini
#################################### Auth LDAP ##########################
[auth.ldap]
enabled = true
config_file = /etc/grafana/ldap.toml
allow_sign_up = true

can you please help me resolving this.