试试这个:

System.Net.ServicePointManager.SecurityProtocol = System.Net.SecurityProtocolType.Tls12;

请注意，您必须至少使用4.5 .NET框架

我个人最喜欢以下解决方案:

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

．.． 然后在请求获取错误之前，执行以下操作

System.Net.ServicePointManager.ServerCertificateValidationCallback = delegate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors) { return true; };

这是在咨询卢克的解决方案后发现的

我已经用了一段时间了如果有用的话。

调用方必须显式地请求需要不受信任的认证，并在完成时将回调放回默认状态。

    /// <summary>
    /// Helper method for returning the content of an external webpage
    /// </summary>
    /// <param name="url">URL to get</param>
    /// <param name="allowUntrustedCertificates">Flags whether to trust untrusted or self-signed certificates</param>
    /// <returns>HTML of the webpage</returns>
    public static string HttpGet(string url, bool allowUntrustedCertificates = false) {
        var oldCallback = ServicePointManager.ServerCertificateValidationCallback;
        string webPage = "";
        try {
            WebRequest req = WebRequest.Create(url);

            if (allowUntrustedCertificates) {
                // so we can query self-signed certificates
                ServicePointManager.ServerCertificateValidationCallback = 
                    ((sender, certification, chain, sslPolicyErrors) => true);
            }

            WebResponse resp = req.GetResponse();
        
            using (StreamReader sr = new StreamReader(resp.GetResponseStream())) {
                webPage = sr.ReadToEnd().Trim();
                sr.Close();
            }
            return webPage;
        }
        catch {
            // if the remote site fails to response (or we have no connection)
            return null;
        }
        finally {
            ServicePointManager.ServerCertificateValidationCallback = oldCallback;
        }
    }

想法(基于过去的痛苦):

do you have DNS and line-of-sight to the server? are you using the correct name from the certificate? is the certificate still valid? is a badly configured load balancer messing things up? does the new server machine have the clock set correctly (i.e. so that the UTC time is correct [ignore local time, it is largely irrelevent]) - this certainly matters for WCF, so may impact regular SOAP? is there a certificate trust chain issue? if you browse from the server to the soap service, can you get SSL? related to the above - has the certificate been installed to the correct location? (you may need a copy in Trusted Root Certification Authorities) is the server's machine-level proxy set correctly? (which different to the user's proxy); see proxycfg for XP / 2003 (not sure about Vista etc)

如果没有工作坏证书，当ServerCertificateValidationCallback返回true; 我的ServerCertificateValidationCallback代码:

ServicePointManager.ServerCertificateValidationCallback += delegate
{
    LogWriter.LogInfo("Проверка сертификата отключена, на уровне ServerCertificateValidationCallback");
    return true;
};

我的代码被阻止执行ServerCertificateValidationCallback:

     if (!(ServicePointManager.CertificatePolicy is CertificateValidation))
    {
        CertificateValidation certValidate = new CertificateValidation();
        certValidate.ValidatingError += new CertificateValidation.ValidateCertificateEventHandler(this.OnValidateCertificateError);
        ServicePointManager.CertificatePolicy = certValidate;
    }

OnValidateCertificateError功能:

private void OnValidateCertificateError(object sender, CertificateValidationEventArgs e)
{
    string msg = string.Format(Strings.OnValidateCertificateError, e.Request.RequestUri, e.Certificate.GetName(), e.Problem, new Win32Exception(e.Problem).Message);
    LogWriter.LogError(msg);
    //Message.ShowError(msg);
}

我禁用了CertificateValidation代码和ServerCertificateValidationCallback运行得很好

在我的情况下，我试图在Visual Studio环境中使用IIS 7测试SSL。

这是我最后做的让它工作:

在我的网站的“绑定…”在IIS中，我必须添加“https”绑定到端口443，并选择“IIS Express development Certificate”。 在我的网站的“高级设置…”我必须将“启用的协议”从“http”更改为“https”。 在“SSL设置”图标下，我选择了客户端证书的“接受”。 然后我不得不回收应用程序池。 我还必须使用mmc.exe将本地主机证书导入我的个人存储。

我的网络。配置文件已经正确配置，所以在我把上面所有的东西都整理好之后，我就可以继续测试了。