diff --git a/htdocs/core/class/ldap.class.php b/htdocs/core/class/ldap.class.php
index 48618a83dd9..fa8f05873a6 100644
--- a/htdocs/core/class/ldap.class.php
+++ b/htdocs/core/class/ldap.class.php
@@ -301,7 +301,8 @@ class Ldap
 	 */
 	public function close()
 	{
-		if ($this->connection && !@ldap_close($this->connection)) {
+		$r_type = get_resource_type($this->connection);
+		if ($this->connection && ($r_type === "Unknown" || !@ldap_close($this->connection))) {
 			return false;
 		} else {
 			return true;