Unable to connect LDAP through USER

Hi,

I have integrated ldap connection and test account has given success parameter (ldap error #82 Success).
I am able to connect through core php code, but unable to connect through LDAP. So could you please help me on this.

My LDAP server details:

sid = TrainzKM
numeric_sid = 1
name = TrainzKM
status = 1
ldap_type = default
address = 172.16.0.5
port = 389
tls = 0
followrefs = 0
bind_method = 3
basedn = xxxxxxxxxxxxxxxx
binddn = xxxxxxxxxxxxxxxxxxxxxxx
user_dn_expression = xxxxxxxxxxxxxxxxxx
user_attr = samaccountname
account_name_attr = samaccountname
mail_attr = mail
mail_template =
picture_attr = thumbnailphoto
unique_persistent_attr =
unique_persistent_attr_binary = 0
ldap_to_drupal_user =
testing_drupal_username = xxxxxxxxxxxxxxxxxxxx
testing_drupal_user_dn =xxxxxxxxxxxxxxxxxxx
grp_unused = 0
grp_object_cat =
grp_nested = 0
grp_user_memb_attr_exists = 0
grp_user_memb_attr =
grp_memb_attr =
grp_memb_attr_match_user_attr =
grp_derive_from_dn = 0
grp_derive_from_dn_attr =
grp_test_grp_dn =
grp_test_grp_dn_writeable =
search_pagination = 0
search_page_size = 1000