smtp。gmail。com异常，启用发送电子邮件

Question

当我使用gmail smtp获得异常时，我遇到了一个问题。

1） 允许不太安全的应用：打开

2）尝试过的端口587, 465, 25（相同的例外）

3）尝试禁用SSL（相同的例外）

4） smtp的telnet。gmail。用于端口465、587的com，以及从用于smtp的电子邮件地址直接发送

思想？

public async Task SendEmail(string subject, string message)
{
    MailAddress fromAddress = new MailAddress("[e-mail]");
    MailAddress toAddress = new MailAddress("[e-mail]");

    MailMessage mail = new MailMessage(fromAddress.Address, toAddress.Address);
    mail.Subject = subject;
    mail.Body = message;

    SmtpClient client = new SmtpClient();
    client.Host = "smtp.gmail.com";
    client.Port = 587;
    client.DeliveryMethod = SmtpDeliveryMethod.Network;
    client.EnableSsl = true;
    client.Timeout = 20000;
    client.UseDefaultCredentials = false;
    client.Credentials = new NetworkCredential("[e-mail]", "password");

    try
    {
        client.Send(mail);
    } 
    catch (Exception ex)
    {
        Console.Write(ex.Message);
    }
}

使用端口587的异常：

{System.Net.Mail.SmtpException: The operation has timed out.
    at System.Net.Mail.SmtpClient.Send(MailMessage message)
    at EmailsUtilities.<SendEmail>d__1.MoveNext() in client.Send(mail);

使用端口465的异常：

{System.Net.Mail.SmtpException: Failure sending mail. ---> 
System.IO.IOException: Unable to read data from the transport connection: The 
connection was closed.
   at System.Net.Mail.SmtpReplyReaderFactory.ProcessRead(Byte[] buffer, Int32 
offset, Int32 read, Boolean readLine)
    at System.Net.Mail.SmtpReplyReaderFactory.ReadLines(SmtpReplyReader 
caller, Boolean oneLine)
   at System.Net.Mail.SmtpReplyReaderFactory.ReadLine(SmtpReplyReader caller)
   at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port)
   at System.Net.Mail.SmtpTransport.GetConnection(String host, Int32 port)
   at System.Net.Mail.SmtpClient.GetConnection()
   at System.Net.Mail.SmtpClient.Send(MailMessage message)
   --- End of inner exception stack trace ---
  at System.Net.Mail.SmtpClient.Send(MailMessage message)
  at EmailsUtilities.<SendEmail>d__1.MoveNext() in client.Send(mail);

更新：更改客户端后。发送（mail）到等待客户端。SendMailAsync（mail）获取新异常：

{System.Net.Mail.SmtpException: Syntax error, command 
unrecognized. The server response was: 
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at 
System.Net.Mail.SmtpConnection.ConnectAndHandshakeAsyncResult.End(IAsyncResult 
 result)
   at System.Net.Mail.SmtpTransport.EndGetConnection(IAsyncResult result)
   at System.Net.Mail.SmtpClient.ConnectCallback(IAsyncResult result)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at 
System.Runtime.CompilerServices.TaskAwaiter
    .HandleNonSuccessAndDebuggerNotificati 
   on(Task task)
       at EmailsUtilities.<SendEmail>d__1.MoveNext() in client.SendMailAsync 
    System.Net.Mail.SmtpException

感谢任何帮助！

Answer 1

最后使用Mail.dll（通过NuGet安装）获得电子邮件。示例：

IMail email = Mail
    .Html(@"Html with an image: <img src=""cid:lena"" />")
    .AddVisual(@"c:\lena.jpeg").SetContentId("lena")
    .AddAttachment(@"c:\tmp.doc").SetFileName("document.doc")
    .To("[e-mail]")
    .From("[e-mail]")
    .Subject("Subject")
    .Create();

using(Smtp smtp = new Smtp())
{
    smtp.Connect("smtp.server.com");  // or ConnectSSL for SSL
    smtp.UseBestLogin("user", "password");
    smtp.SendMessage(email);                     
    smtp.Close();   
}