LDAP stop working after an upgrade

Hello everyone,

I just got a LDAP problem after upgrading our OCS server, i can't connect to it using my LDAP account.

OS version : centos 6.8 (2.6.32-642.11.1.el6.x86_64)

PHP version : 5.6.31

OCS server : 2.3.1

Agent version : still 2.1.1

Error log :

[Mon Aug 21 11:29:11 2017] [error] [client X.X.X.X] PHP Warning:  ldap_connect(): Could not create session handle: Bad parameter to an ldap routine in /usr/share/ocsinventory-reports/ocsreports/backend/AUTH/methode/ldap.php on line 124, referer: https://par-abv-ocs/ocsreports/
[Mon Aug 21 11:29:11 2017] [error] [client X.X.X.X] PHP Warning:  ldap_set_option(): supplied argument is not a valid ldap link resource in /usr/share/ocsinventory-reports/ocsreports/backend/AUTH/methode/ldap.php on line 127, referer: https://par-abv-ocs/ocsreports/
[Mon Aug 21 11:29:11 2017] [error] [client X.X.X.X] PHP Warning:  ldap_set_option(): supplied argument is not a valid ldap link resource in /usr/share/ocsinventory-reports/ocsreports/backend/AUTH/methode/ldap.php on line 128, referer: https://par-abv-ocs/ocsreports/
[Mon Aug 21 11:29:11 2017] [error] [client X.X.X.X] PHP Warning:  ldap_bind() expects parameter 1 to be resource, boolean given in /usr/share/ocsinventory-reports/ocsreports/backend/AUTH/methode/ldap.php on line 130, referer: https://par-abv-ocs/ocsreports/
[Mon Aug 21 11:29:11 2017] [error] [client X.X.X.X] PHP Warning:  ldap_search(): supplied argument is not a valid ldap link resource in /usr/share/ocsinventory-reports/ocsreports/backend/AUTH/methode/ldap.php on line 76, referer: https://par-abv-ocs/ocsreports/
[Mon Aug 21 11:29:11 2017] [error] [client X.X.X.X] PHP Warning:  ldap_count_entries() expects parameter 1 to be resource, boolean given in /usr/share/ocsinventory-reports/ocsreports/backend/AUTH/methode/ldap.php on line 77, referer: https://par-abv-ocs/ocsreports/
[Mon Aug 21 11:29:11 2017] [error] [client X.X.X.X] PHP Warning:  ldap_get_entries() expects parameter 1 to be resource, boolean given in /usr/share/ocsinventory-reports/ocsreports/backend/AUTH/methode/ldap.php on line 78, referer: https://par-abv-ocs/ocsreports/
[Mon Aug 21 11:29:11 2017] [error] [client X.X.X.X] PHP Warning:  ldap_close() expects parameter 1 to be resource, boolean given in /usr/share/ocsinventory-reports/ocsreports/backend/AUTH/methode/ldap.php on line 79, referer: https://par-abv-ocs/ocsreports/

Package installed :

php56w-cli-5.6.31-1.w6.x86_64
php56w-opcache-5.6.31-1.w6.x86_64
php56w-ldap-5.6.31-1.w6.x86_64
php56w-common-5.6.31-1.w6.x86_64
php56w-pdo-5.6.31-1.w6.x86_64
php56w-5.6.31-1.w6.x86_64
php56w-mbstring-5.6.31-1.w6.x86_64
php56w-gd-5.6.31-1.w6.x86_64
php56w-mysql-5.6.31-1.w6.x86_64
php56w-soap-5.6.31-1.w6.x86_64
openldap-clients-2.4.40-16.el6.x86_64
openldap-2.4.40-16.el6.x86_64
apr-util-ldap-1.3.9-3.el6_0.1.x86_64