diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/WechatTenpayClient.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/WechatTenpayClient.cs
index 3299cfcf..783f19fd 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/WechatTenpayClient.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/WechatTenpayClient.cs
@@ -175,7 +175,7 @@ namespace SKIT.FlurlHttpClient.Wechat.TenpayV2
                     string json = JsonSerializer.Serialize(data);
                     string xml = Utilities.XmlUtility.ConvertFromJson(json);
 
-                    using HttpContent httpContent = new StringContent(xml, Encoding.UTF8, "text/xml");
+                    using HttpContent httpContent = new StringContent(xml, Encoding.UTF8, "application/xml");
                     using IFlurlResponse flurlResponse = await SendRequestAsync(flurlRequest, httpContent: httpContent, cancellationToken);
                     return await WrapResponseWithXmlAsync<T>(flurlResponse, cancellationToken);
                 }
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/WechatTenpayEndpoints.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/WechatTenpayEndpoints.cs
index eaf58479..f1be0835 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/WechatTenpayEndpoints.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/WechatTenpayEndpoints.cs
@@ -1,4 +1,6 @@
-namespace SKIT.FlurlHttpClient.Wechat.TenpayV2
+using System;
+
+namespace SKIT.FlurlHttpClient.Wechat.TenpayV2
 {
     /// <summary>
     /// 微信支付 API 接口域名。
@@ -18,6 +20,7 @@
         /// <summary>
         /// 沙箱域名。
         /// </summary>
-        public const string SANDBOX = "https://api.mch.weixin.qq.com/sandboxnew";
+        [Obsolete("")]
+        public const string SANDBOX = "https://api.mch.weixin.qq.com/xdc/apiv2sandbox";
     }
 }