---
tags: Web, C#
authors: Anderson
---

###### tags: `Web` `C#`
# error : System.Net.WebException: The request was aborted: Could not create SSL/TLS secure channel.

## :memo: 問題
error : System.Net.WebException: The request was aborted: Could not create SSL/TLS secure channel.
## :memo: 原因
因對象網站使用的安全協定關閉較舊的版本SSL3.0/TLS1.0/TLS1.1
來源:[SSL3.0/TLS1.0/TLS1.1壽終正寢 主流瀏覽器擁抱TLS1.2/TLS1.3](https://kknews.cc/tech/9zoyvzl.html)

## :memo: 解決
設定使用的安全協定

**ServicePointManager.Expect100Continue = true;
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;**

參考:
1. [The request was aborted: Could not create SSL/TLS secure channel](https://stackoverflow.com/questions/2859790/the-request-was-aborted-could-not-create-ssl-tls-secure-channel)
2. [C# 連線 HTTPS 網站發生驗證失敗導致基礎連接已關閉](https://blog.darkthread.net/blog/webclient-and-tls12/)

Private void DownloadData()
{
    ServicePointManager.Expect100Continue = true;
    ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

    var jsonStr = new WebClient().DownloadString("http://portal.sw.nat.gov.tw/APGQ/GC331!downLoad?formBean.downLoadFile=CURRENT_JSON");

    JObject jsonObject = JsonConvert.DeserializeObject<JObject>(jsonStr);
    var startDate = this.ParseToDateString(jsonObject["start"].ToString());
    var endDate = this.ParseToDateString(jsonObject["end"].ToString());
    var items = jsonObject["items"].ToString();
}

## :memo: 補充
[快速檢測網站是否已關閉 TLS 1.1/1.0](https://blog.darkthread.net/blog/check-tls-version/)
[檢測網站](https://www.ssllabs.com/ssltest/")