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:5.7.0在.net核心中需要身份验证

我收到这个错误

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:5.7.0需要身份验证。

当用户试图从网站发送忘记密码的电子邮件时。帮帮我,我该怎么修?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Mail;
using System.Web;

namespace ERP.Senders
{
    public class SendEmail
    {
        public static void Send(string to,string subject,string body)
        {
            MailMessage mail = new MailMessage();

            SmtpClient SmtpServer = new SmtpClient("smtp.gmail.com");

            mail.From = new MailAddress("[email protected]","سامانه مدیریت منابع انسانی ERP");
            mail.To.Add(to);
            mail.Subject = subject;
            mail.Body = body;
            mail.IsBodyHtml = true;

            //System.Net.Mail.Attachment attachment;
            // attachment = new System.Net.Mail.Attachment("c:/textfile.txt");
            // mail.Attachments.Add(attachment);
            SmtpServer.Port = 587;
            SmtpServer.Credentials = new System.Net.NetworkCredential("[email protected]", "*******");
            SmtpServer.EnableSsl = true;

            SmtpServer.Send(mail);
        }
    }
}