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)

微软的SSL诊断工具可能能够帮助识别问题。

更新链接已经修复。

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

我在Internet Explorer的. net应用程序中遇到了类似的问题。

我解决了将证书(在我的例子中是VeriSign Class 3证书)添加到受信任编辑器证书的问题。

Go to Internet Options-> Content -> Publishers and import it

您可以通过以下方式导出证书:

Internet Options-> Content -> Certificates -> Intermediate Certification Authorities -> VeriSign Class 3 Public Primary Certification Authority - G5

谢谢

如果您不想盲目地信任所有人，只对某些主机设置信任例外，那么下面的解决方案更合适。

public static class Ssl
{
    private static readonly string[] TrustedHosts = new[] {
      "host1.domain.com", 
      "host2.domain.com"
    };

    public static void EnableTrustedHosts()
    {
      ServicePointManager.ServerCertificateValidationCallback = 
      (sender, certificate, chain, errors) =>
      {
        if (errors == SslPolicyErrors.None)
        {
          return true;
        }

        var request = sender as HttpWebRequest;
        if (request != null)
        {
          return TrustedHosts.Contains(request.RequestUri.Host);
        }

        return false;
      };
    }
}

那就打电话给Ssl。当你的应用启动时启用托管主机。