帮助电子邮件发件人一些错误

我正在使用c＃处理电子邮件应用程序并且电子邮件没有收到代码

iam working on an e mail application using c# and the email doesn,t receive the code

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Net.Mail;
using System.Net;
namespace webclient
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            
        }

        private void Form1_Load(object sender, EventArgs e)
        {
          
            


        }
        
        private void button1_Click(object sender, EventArgs e)
        {
          
                MailMessage message = new MailMessage();
                message.From = new MailAddress(textBox4.Text);
                message.Subject = textBox2.Text;
                message.Body = textBox3.Text;
                foreach (string s in textBox1.Text.Split(';'))
                    message.To.Add(s);
                SmtpClient client = new SmtpClient();
                client.Credentials = new NetworkCredential(textBox4.Text, textBox5.Text);
                client.Host = "smtp.gmail.com";
                client.Port = 587;
                client.EnableSsl = true;
                client.Send(message);
            
       
        }

        private void groupBox1_Enter(object sender, EventArgs e)
        {

        }

        private void pictureBox1_Click(object sender, EventArgs e)
        {

        }

        private void textBox1_TextChanged_1(object sender, EventArgs e)
        {

        }

        private void button1_Click_1(object sender, EventArgs e)
        {

        }
        }
    }