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。

如果你使用的是Windows 2003，你可以这样做:

Open Microsoft Management Console (Start --> Run --> mmc.exe); Choose File --> Add/Remove Snap-in; In the Standalone tab, choose Add; Choose the Certificates snap-in, and click Add; In the wizard, choose the Computer Account, and then choose Local Computer. Press Finish to end the wizard; Close the Add/Remove Snap-in dialog; Navigate to Certificates (Local Computer) and choose a store to import: If you have the Root CA certificate for the company that issued the certificate, choose Trusted Root Certification Authorities; If you have the certificate for the server itself, choose Other People Right-click the store and choose All Tasks --> Import Follow the wizard and provide the certificate file you have; After that, simply restart IIS and try calling the web service again.

参考:http://www.outsystems.com/NetworkForums/ViewTopic.aspx?Topic=Web-Services: -Could-not-establish-trust-relationship-for-the-SSL / TLS -…

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

下面的代码片段将修复您正在调用的服务器上的SSL证书有问题的情况。例如，证书可能是自签名的，或者证书和服务器之间的主机名可能不匹配。

如果您正在调用您直接控制之外的服务器，这是危险的，因为您不能再确定您正在与您认为连接到的服务器通信。但是，如果您处理的是内部服务器，而获得“正确的”证书是不现实的，请使用以下命令告诉web服务忽略证书问题并勇敢地继续工作。

前两个使用lambda表达式，第三个使用常规代码。第一个接受任何证书。后两者至少检查证书中的主机名是否是您所期望的主机名。 ．.． 希望对你有帮助

//Trust all certificates
System.Net.ServicePointManager.ServerCertificateValidationCallback =
    ((sender, certificate, chain, sslPolicyErrors) => true);

// trust sender
System.Net.ServicePointManager.ServerCertificateValidationCallback
                = ((sender, cert, chain, errors) => cert.Subject.Contains("YourServerName"));

// validate cert by calling a function
ServicePointManager.ServerCertificateValidationCallback += new RemoteCertificateValidationCallback(ValidateRemoteCertificate);

// callback used to validate the certificate in an SSL conversation
private static bool ValidateRemoteCertificate(object sender, X509Certificate cert, X509Chain chain, SslPolicyErrors policyErrors)
{
    bool result = cert.Subject.Contains("YourServerName");
    return result;
}

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

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