diff --git a/src/Panel/MailPanel.php b/src/Panel/MailPanel.php
index b0470702e..609f1c31c 100644
--- a/src/Panel/MailPanel.php
+++ b/src/Panel/MailPanel.php
@@ -67,7 +67,7 @@ public function initialize(): void
 
             $configs[$name] = $transport;
         }
-        $property->setValue($configs);
+        $reflection->setStaticPropertyValue('_config', $configs);
     }
 
     /**