c# – “16位ms-dos子系统”错误

代码有什么问题吗？

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


namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            var fromAddress = new MailAddress("aaa@gmail.com","System");           
            var toAddress = new MailAddress("bbb@gmail.com","Receiver");
            const string fromPassword = "xxx";

            const string subject = "Message";

            string body = args[0];


            var smtp = new SmtpClient
            {
                Host = "smtp.gmail.com",Port = 587,EnableSsl = true,DeliveryMethod = SmtpDeliveryMethod.Network,UseDefaultCredentials = false,Credentials = new NetworkCredential(fromAddress.Address,fromPassword)
            };
            using (var message = new MailMessage(fromAddress,toAddress)
            {
                Subject = subject,Body = body
            })
            {
                smtp.Send(message);
            }

        }
    }
}