diff --git a/public_html/includes/class/class.LSauthMethod.php b/public_html/includes/class/class.LSauthMethod.php
index b269e24b..d45fb93f 100644
--- a/public_html/includes/class/class.LSauthMethod.php
+++ b/public_html/includes/class/class.LSauthMethod.php
@@ -60,7 +60,7 @@ class LSauthMethod {
 			$result = $authobject -> searchObject(
 				$this -> authData['username'],
 				LSsession :: getTopDn(),
-				LSsession :: $ldapServer['authObjectFilter']
+				(isset(LSsession :: $ldapServer['authObjectFilter'])?LSsession :: $ldapServer['authObjectFilter']:NULL)
 			);
 			$nbresult=count($result);