認證錯誤發送郵件從雅虎在C＃窗口應用程序

我想從我的軟件使用smtp雅虎發送電子郵件，但它顯示以下錯誤「SMTP服務器需要安全連接或客戶端未經過身份驗證。服務器響應是：5.7.1需要驗證「。認證錯誤發送郵件從雅虎在C＃窗口應用程序

我知道關於在谷歌較不安全的應用程序設置，但我不知道在雅虎的設置。 gmail賬戶憑證可以運行相同的代碼。這裏是供參考的代碼。

string EmailFrom = "[email protected]"; 
     string EmailTo = "[email protected]"; 
     string PassWord = "test123"; 
     string EmailHost = "smtp.mail.yahoo.com"; 
     string status = ""; 
     string Body = ""; 

     MailMessage message = new MailMessage(); 
     SmtpClient smtp = new SmtpClient(); 

     message.From = new MailAddress(EmailFrom); 
     message.To.Add(new MailAddress(EmailTo)); 
     message.Subject = "Auto Backup at test" ; 
     message.Body = "Backup has been taken at test on" + DateTime.Now; 
     Body = "Backup has been taken at test on" + DateTime.Now; 
     smtp.Port = 587; 
     smtp.Host = EmailHost; 
     smtp.EnableSsl = true; 
     smtp.UseDefaultCredentials = false; 
     smtp.Credentials = new NetworkCredential(EmailFrom, PassWord); 
     smtp.DeliveryMethod = SmtpDeliveryMethod.Network; 
     //ServiceLogLibrary.WriteErrorlog("Step:5"); 
     //Library.WriteErrorlog("Before sending mail"); 
     smtp.Send(message);

來源

2016-11-14 Sasuke Uchiha