C#发送邮件失败，使用System.Net.Mail.SmtpClient发送失败解决，推荐用System.Web.Mail.SmtpMail发送邮件，一次成功

System.Net.Mail.SmtpClient一般发送如果启用了ssl则他会先从25端口去建立握手，一般邮件服务器都会禁用25端口，因此会发送报错，远程服务器无响应，连接超时

推荐用web方式发送邮件，这样成功率很高，需要引用C#的程序集组件System.Web

参考代码：

   public static void SendEmail()
        {
            //发件人
            const string sendAddress = "[email protected]";
            //发件人密码
            const string sendPassword = "123456";
            //收件人
            const string receiveAddress = "[email protected]";

            System.Web.Mail.MailMessage mail = new System.Web.Mail.MailMessage();
            try
            {
                mail.From = sendAddress;
                mail.To = receiveAddress;
                mail.Subject = "whl测试发送邮件2-26-1";
                mail.BodyFormat = System.Web.Mail.MailFormat.Html;
                mail.Body = "whl发送的测试邮件" + DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");

                mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", "1"); //basic authentication
                mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusername", sendAddress); //set your username here 发件人邮箱
                mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword", sendPassword); //set your password here 发件人邮箱密码
                mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpserverport", 465);//发送端口号
                mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpusessl", "true");//是否启用ssl
                
                //需要引用组件System.Web
                System.Web.Mail.SmtpMail.SmtpServer = "msg.petrochina.com.cn";
                System.Web.Mail.SmtpMail.Send(mail);

                Console.WriteLine("发送邮件成功");
            }
            catch (Exception ex)
            {
                var exg = ex.InnerException ?? ex;
                string msg = exg.ToString();
                Console.WriteLine(msg);
            }
        }

 

转载：

https://blog.csdn.net/molu474305148/article/details/99713389

https://www.cnblogs.com/tsql/p/9078163.html