SMTP 服务器需要安全连接或客户端未通过身份验证。

Posted 2023-03-31

【中文标题】SMTP 服务器需要安全连接或客户端未通过身份验证。

【英文标题】：The SMTP server requires a secure connection or the client was not authenticated.

【发布时间】：2013-12-02 20:41:19

【问题描述】：

命名空间邮件代码 课堂节目 静态无效主要（字符串 [] 参数） SendEmailToInformCustomerForNewOrderMessage();

    public static void SendEmailToInformCustomerForNewOrderMessage()
               
        try
        
            SendMail();
        
        catch (Exception ex)
        
            Logger.Write(CreateExceptionString(ex));
        
    

    public static void SendMail()
    

        try
        
            // Gmail Address from where you send the mail      
            dynamic fromAddress = "[e-mail]";
            // any address where the email will be sending
            dynamic toAddress = "[e-mail]";

            //Password of your gmail address
            const string fromPassword = "password";
            // Passing the values and make a email formate to display
            string subject = "test mail code";
            string body = "From: " + "Puneet";
            body += "Email: " + "[e-mail]";
            body += "Subject: " + "Test email code";
            body += "Question: " + "test question";
            // smtp settings
            dynamic smtp = new System.Net.Mail.SmtpClient();
            if (true)
            
                smtp.Host = "smtp.gmail.com";
                smtp.Port = 587;
                smtp.EnableSsl = true;
                smtp.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
                smtp.Credentials = new NetworkCredential(fromAddress, fromPassword);
                smtp.UseDefaultCredentials = false;
                smtp.Timeout = 20000;
            
            // Passing values to smtp object
            dynamic message = new MailMessage(fromAddress, toAddress, subject, body);
            smtp.Send(message);
        
        catch (Exception ex)
        
            Logger.Write(CreateExceptionString(ex));
        
    

    public static string CreateExceptionString(Exception e)
    
        StringBuilder sb = new StringBuilder();
        CreateExceptionString(sb, e, string.Empty);

        return sb.ToString();
    

    private static void CreateExceptionString(StringBuilder sb, Exception e, string indent)
    
        if (indent == null)
        
            indent = string.Empty;
        
        else if (indent.Length > 0)
        
            sb.AppendFormat("0Inner ", indent);
        

        sb.AppendFormat("Exception Found:" + "& vbLf &" + "0Type: 1", indent, e.GetType().FullName);
        sb.AppendFormat("& vbLf &" + "0Message: 1", indent, e.Message);
        sb.AppendFormat("& vbLf &" + "0Source: 1", indent, e.Source);
        sb.AppendFormat("& vbLf &" + "0Stacktrace: 1", indent, e.StackTrace);

        if (e.InnerException != null)
        
            sb.Append("& vbLf &");
            CreateExceptionString(sb, e.InnerException, indent + "  ");
        
    

    public sealed class Logger
    

        //
        // TODO: Add constructor logic here    
        public static void Write(string value)
        
            StreamWriter writetext = new StreamWriter(AppDomain.CurrentDomain.BaseDirectory+"exceptionfile.txt");
            writetext.WriteLine(value);
            writetext.Close();
        
    
      

我在这个测试 C# 控制台应用程序中发生错误。请帮助我并解决这个问题。错误

【参考方案1】：

你的代码有问题：

你需要交换这两行：

smtp.Credentials = new NetworkCredential(fromAddress, fromPassword);
smtp.UseDefaultCredentials = false;

到这里：

smtp.UseDefaultCredentials = false;
smtp.Credentials = new NetworkCredential(fromAddress, fromPassword);

否则认证失败。

此外，gmail SMTP 服务器采用防洪系统，可防止您向其发送垃圾邮件。如果您执行的发送次数过多或尝试连接失败次数过多，可能会在短时间内禁止您的 IP。

您应该在代码中处理此类情况并稍后重试。