如何修复GMail SMTP错误：“SMTP服务器需要安全连接，或者客户端未通过身份验证。”

提问者：小点点

如何修复GMail SMTP错误：“SMTP服务器需要安全连接，或者客户端未通过身份验证。”

下面是我正在使用的代码。请在下面找到错误消息。请告知如何纠正此问题。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using System.Net;
using System.Net.Mail;

public partial class mailtest : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}

protected void SendEmail(object sender, EventArgs e)
{
    lblmsg.Text = "";
    try
    {
        using (MailMessage mm = new MailMessage(txtEmail.Text, txtTo.Text))
        {
            mm.Subject = txtSubject.Text;
            mm.Body = txtBody.Text;
            //if (fuAttachment.HasFile)
            //{
            //    string FileName = Path.GetFileName(fuAttachment.PostedFile.FileName);
            //    mm.Attachments.Add(new Attachment(fuAttachment.PostedFile.InputStream, FileName));
            //}
            mm.IsBodyHtml = false;
            SmtpClient smtp = new SmtpClient();
            smtp.Host = txtsmtphost.Text.Trim();
            smtp.EnableSsl = false;
            if (chkssl.Checked == true)
            {
                smtp.EnableSsl = true;
            }
            NetworkCredential NetworkCred = new NetworkCredential(txtEmail.Text, txtPassword.Text);
            smtp.UseDefaultCredentials = true;
            smtp.Credentials = NetworkCred;
            smtp.Port = int.Parse(txtport.Text);
            smtp.Send(mm);
            lblmsg.ForeColor = System.Drawing.Color.DarkGreen;
            lblmsg.Text = "Email sent successfuly !!";
            //ClientScript.RegisterStartupScript(GetType(), "alert", "alert('Email sent successfuly !!');", true);
        }
    }
    catch (Exception ex)
    {
        lblmsg.ForeColor = System.Drawing.Color.Red;
        lblmsg.Text = "Failed " + ex.ToString();
        ClientScript.RegisterStartupScript(GetType(), "alert", "alert('Failed');", true);
    }
}}

下面的错误消息

系统网邮政SmtpException:SMTP服务器需要安全连接，或者客户端未通过身份验证。服务器响应为：5.7。需要0身份验证。在系统中了解更多信息。网邮政MailCommand。系统上的CheckResponse（SmtpStatusCode状态码、字符串响应）。网邮政MailCommand。在系统上发送（SmtpConnection conn，Byte[]命令，maildAddress from，布尔allowinicode）。网邮政短程运输。SendMail（MailAddress发件人、MailAddressCollection收件人、字符串deliveryNotify、布尔AllowInCode、SmtpFailedRecipientException

共2个答案

匿名用户

SMTP服务器需要安全连接，否则客户端未通过身份验证。

要修复此错误，请转到您的google帐户并生成应用程序密码

运行代码时，请使用生成的密码，而不是实际用户密码。

当帐户启用2fa时，这种情况最常见。

using System;
using System.Net;
using System.Net.Mail;

namespace GmailSmtpConsoleApp
{
    class Program
    {
        private const string To = "test@test.com";
        private const string From = "test@test.com";
        
        private const string GoogleAppPassword = "XXXXXXXX";
        
        private const string Subject = "Test email";
        private const string Body = "<h1>Hello</h1>";
        
        
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
            
            var smtpClient = new SmtpClient("smtp.gmail.com")
            {
                Port = 587,
                Credentials = new NetworkCredential(From , GoogleAppPassword),
                EnableSsl = true,
            };
            var mailMessage = new MailMessage
            {
                From = new MailAddress(From),
                Subject = Subject,
                Body = Body,
                IsBodyHtml = true,
            };
            mailMessage.To.Add(To);

            smtpClient.Send(mailMessage);
        }
    }
}

匿名用户

你应该在你用来发送电子邮件的Gmail帐户上启用不太安全的应用程序设置。您可以使用此链接启用设置。

有关您的问题的更多信息，请访问此处。