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件人，但它显示错误是：

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

private void SendHtmlFormattedEmail(string recepientEmail, string subject, string body)
{
    using (MailMessage mailMessage = new MailMessage())
    {
       mailMessage.From = new MailAddress("sysumurugan@gmail.com");
       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("sysumurugan@gmail.com", "XXXXXXXXX");
       smtp.Credentials = NetworkCred;
       smtp.Timeout = 10000;
       smtp.Send(mailMessage);
    }
}

请帮我获取邮件发件人代码示例

状态：System.Net.Mail.SmtpStatusCode.MustIssueStartTlsFirst

Answer 1

尝试像这样交换这些行：

smtp.UseDefaultCredentials = false;
System.Net.NetworkCredential NetworkCred = new    System.Net.NetworkCredential("sysumurugan@gmail.com", "XXXXXXXXX");

Answer 2

我访问了以下链接： https://www.google.com/settings/security/lesssecureapps

并打开选项访问不太安全的应用程序