hi , I can't import the survey participants from ldap and system shown this error :

Notice: Constant LDAP_OPT_DIAGNOSTIC_MESSAGE already defined in /volume1/web/LimeSurvey/application/controllers/admin/tokens.php on line 1883

the below is the ldap.php setting :

$serverId = 0;
$ldap_server[$serverId] = "l72.16.2.184";
$ldap_server[$serverId] = "389";
$ldap_server[$serverId] = "ldapv2";
$ldap_server[$serverId] = "none";
$ldap_server[$serverId] = false;
$ldap_server[$serverId] = "CN=administrator,CN=users,DC=xxx,DC=yyy";
$ldap_server[$serverId] = "password";
$query_id = 0;
$ldap_queries[$query_id] = 0;
$ldap_queries[$query_id] = 'Staff with an enabled account';
$ldap_queries[$query_id] = 'OU=Users,DC=xxx,DC=yyy';
$ldap_queries[$query_id] = '(&(objectCategory=Person)(objectClass=user)(!(userAccountControl=514)))';
$ldap_queries[$query_id] = 'sub';
$ldap_queries[$query_id] = 'givenname';
$ldap_queries[$query_id] = 'sn';
$ldap_queries[$query_id] = 'mail';


LimeSurvey Version : 3.15.0+181008

How to fix this error ?? thanks !