使用C#发送电子邮件SMTP服务器需要安全连接或客户端未通过身份验证[重复]

Question

我正在使用C#创建示例电子邮件发送器，但它显示一个错误是：

SMTP服务器需要安全连接或客户端未通过身份验证。服务器响应为：5.5.1需要身份验证。

private void SendHtmlFormattedEmail(string recepientEmail, string subject, string body)
{
    using (MailMessage mailMessage = new MailMessage())
    {
       mailMessage.From = new MailAddress("[e-mail]");
       mailMessage.Subject = subject;
       mailMessage.Body = body;
       mailMessage.To.Add(new MailAddress(recepientEmail));
       SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
       smtp.EnableSsl = true;
       smtp.UseDefaultCredentials = false;
       System.Net.NetworkCredential NetworkCred = new System.Net.NetworkCredential("[e-mail]", "XXXXXXXXX");
       smtp.Credentials = NetworkCred;
       smtp.Timeout = 10000;
       smtp.Send(mailMessage);
    }
}

请帮助我获取邮件发件人代码示例

状态：System.Net.Mail.SMTPStatusCode.MusTissuestarttlsFirst

Answer 1

试着交换这些行,如下所示：

smtp.UseDefaultCredentials = false;
System.Net.NetworkCredential NetworkCred = new    System.Net.NetworkCredential("[e-mail]", "XXXXXXXXX");