Could not authorize you from Ldapmain because "Invalid credentials"

Hello,
Got an issue with LDAPS authentication.
Packages used : gitlab-ce-7.10.1~omnibus.2-1.x86_64 and openldap-2.4.23-31.el6.x86_64

Here is the contens of section in /etc/gitlab/gitlab.rb :
gitlab_rails[‘ldap_servers’] = YAML.load <<-‘EOS’
main:
label: ‘LDAPS’
host: ‘192.21.238.15’
port: 1636
uid: ‘github’
method: ‘ssl’ # “tls” or “ssl” or “plain”
bind_dn: ‘cn=github,ou=technicalAccounts,dc=sg,dc=com’
password: ‘********’
base: ‘ou=active,ou=people,dc=sg,dc=com’
user_filter: ‘sggroupid={0}’
EOS

When I check the logs on openldap, I can see the connction but filter in not provided :
slapd[73470]: conn=1399548 op=2 SRCH base=“ou=active,ou=people,dc=sg,dc=com” scope=2 deref=0 filter="(?=undefined)"

Does anybody has an idea ?
Regards