diff --git a/v2rayN/v2rayN/Views/AddServerWindow.xaml.cs b/v2rayN/v2rayN/Views/AddServerWindow.xaml.cs
index 4db3fa2c..bf0dd3d9 100644
--- a/v2rayN/v2rayN/Views/AddServerWindow.xaml.cs
+++ b/v2rayN/v2rayN/Views/AddServerWindow.xaml.cs
@@ -1,4 +1,5 @@
 using ReactiveUI;
+using System.Net.Security;
 using System.Reactive.Disposables;
 using System.Windows;
 using System.Windows.Controls;