远程服务器返回错误(401)未经授权

没有权限 设置权限

WebClient client=new WebClient();
//NetworkCredential credentials = new NetworkCredential("名字", "密码");
//client.Credentials = credentials;

未能为 SSL/TLS 安全通道建立信任的解决办法
最简单的办法是:
1,先加入命名空间：

using System.Net.Security;
using System.Security.Authentication;
using System.Security.Cryptography.X509Certificates;

2，再重载CheckValidationResult方法，返回true

public bool RemoteCertificateValidationCallback(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
{ 
    return true;
}

3,然后在HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(url);前面加上如下一行代码：

//基础连接已经关闭: 未能为 SSL/TLS 安全通道建立信任关系。
System.Net.ServicePointManager.ServerCertificateValidationCallback = new System.Net.Security.RemoteCertificateValidationCallback(RemoteCertificateValidationCallback);