diff --git a/src/Client/RedmineClient.php b/src/Client/RedmineClient.php
index 0b20430..4978ad3 100644
--- a/src/Client/RedmineClient.php
+++ b/src/Client/RedmineClient.php
@@ -27,6 +27,7 @@ final class RedmineClient
             $item->tag([$api, $method]);
 
             $client = $this->getClient()->getApi($api);
+            $arguments = is_array($arguments) ? $arguments : [];
             $value = \call_user_func_array([$client, $method], $arguments);
 
             return $value;