C＃yandex邮件发送错误5.5.4错误：首先发送AUTH命令

Posted 2021-03-28

我尝试使用C＃和yandex发送邮件，但是我收到一个错误：

错误5.5.4错误：首先发送AUTH命令

这是我的代码。我尝试使用不同的端口（587,465 ..）和SMTP主机（smtp.yandex.com.tr，smtp.yandex.com，smtp.yandex.ru ...），但我得到了所有尝试的相同错误。

SmtpClient sc = new SmtpClient("smtp.yandex.com.tr", 587);
//sc.Port = 587;
//sc.Host = "smtp.yandex.com";

sc.EnableSsl = false;
sc.Credentials = new System.Net.NetworkCredential(System.Configuration.ConfigurationManager.AppSettings["Email"].ToString(), 
                                                  System.Configuration.ConfigurationManager.AppSettings["Sifre"].ToString());
sc.UseDefaultCredentials = false;
sc.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;

答案

Yandex Mail不支持没有SSL的连接（根据https://yandex.com/support/mail/mail-clients.xml）。尝试将EnableSsl设置为true并使用host：smtp.yandex.com，port：465。如果它不起作用 - 尝试端口25

另一答案

你必须在调用sc.Credentials = new System.Net.NetworkCredential()后设置sc.UseDefaultCredentials = false;

UseDefaultCredentials = false将把Credentials重置为null

尝试将行顺序切换为：

sc.UseDefaultCredentials = false;
sc.Credentials = new System.Net.NetworkCredential(System.Configuration.ConfigurationManager.AppSettings["Email"].ToString(), 
                                                  System.Configuration.ConfigurationManager.AppSettings["Sifre"].ToString());

也是smtp.yandex.ru的有效设置：

    smtpUserName=""
    enableSsl="true"
    smtpPassword=""
    smtpAuthentication="Basic"
    smtpServer="smtp.yandex.ru"
    smtpPort="465"

另一答案

如果您的密码错误，将发生此错误。至少对我来说就是这种情况。

另一答案

我解决了这个问题，我将SMTP主机从smtp.yandex.com更改为smtp.yandex.ru，我正在使用端口25.完美地为我工作。这是代码：

EmailCredentials credentials = new EmailCredentials();
    credentials.Domain = "domain.com";
    credentials.SMTPUser = "[e-mail]";
    credentials.SMTPPassword = "pass";
    int SmtpPort = 25;
    string SmtpServer = "smtp.yandex.ru";

    MailMessage EmailMsg = new MailMessage();
    EmailMsg.From = new MailAddress("[e-mail]", "Domain");
    EmailMsg.To.Add(new MailAddress("[e-mail]", "[e-mail]"));
    EmailMsg.ReplyToList.Add("[e-mail]");

    EmailMsg.Subject = "Welcome";

    EmailMsg.Body = "html body code";

    EmailMsg.IsBodyHtml = true;
    EmailMsg.Priority = MailPriority.Normal;

    System.Net.Mail.SmtpClient SMTP = new System.Net.Mail.SmtpClient();
    SMTP.Host = SmtpServer;
    SMTP.Port = SmtpPort;
    SMTP.EnableSsl = true;
    SMTP.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
    SMTP.UseDefaultCredentials = false;
    SMTP.Credentials = new System.Net.NetworkCredential(credentials.SMTPUser, credentials.SMTPPassword);

    SMTP.Send(EmailMsg);