diff --git a/htdocs/societe/class/api_thirdparties.class.php b/htdocs/societe/class/api_thirdparties.class.php
index 4461bb644e3..9f1049544cf 100644
--- a/htdocs/societe/class/api_thirdparties.class.php
+++ b/htdocs/societe/class/api_thirdparties.class.php
@@ -1865,7 +1865,7 @@ class Thirdparties extends DolibarrApi
 		$result = $this->db->query($sql);
 
 		// We do not found an existing SocieteAccount entity for this fk_soc and site ; we then create a new one.
-		if ($result && $this->db->num_rows == 0) {
+		if ($result && $this->db->num_rows($result) == 0) {
 			if (!isset($request_data['key_account'])) {
 				throw new RestException(422, 'Unprocessable Entity: You must pass the key_account attribute in your request data !');
 			}