ASP.NET using gmail with smtp error: "A connection attempt failed because the connected party did not properly respond.."

Question

I'm trying to add a new email confirmation method to my MVC site, so whenever a user registers he will receive a confirmation email. The problem is, that no matter what code I use (I've found some different options on GitHub) I always get the same error:

"A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 66.102.1.108:587".

The code I used is:

using ATMProject.Models;
using Microsoft.AspNet.Identity;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Mail;
using System.Security.Policy;
using System.Web;
using System.Web.Mvc;

namespace ATMProject.Services
{
    public class SendEmailConfirmation
    {
        public string email { get; set; }
        public string fullname { get; set; }
        public string username { get; set; }
        public string random { get; set; }

        public SendEmailConfirmation(string Email, string Fullname, 
          string Username, string Random) 
        {
            email = Email;
            fullname = Fullname;
            username = Username;
            random = Random;
        }

        public void sendEmail ()
        {
            SmtpClient smtp = new SmtpClient();
            smtp.Host = "smtp.gmail.com";
            smtp.Port = 587;
            smtp.UseDefaultCredentials = false;
            smtp.Credentials = new 
              System.Net.NetworkCredential("[email protected]", "123456");
            smtp.EnableSsl = true;
            MailMessage msg = new MailMessage();

            #region Msg
            msg.Subject = "Hello " + fullname;
            msg.Body = "Hello " + fullname + 
              "Thanks for Registering in Budgetize...Your Account Details are given below:";
            msg.Body += "<tr>";
            msg.Body += "<td>User Name :" + username + "</td>";
            msg.Body += "</tr>";
            msg.Body += "<tr>";
            msg.Body += "<td>Activation Number :" + random + "</td>";
            msg.Body += "</tr>";
            msg.Body += "<tr>";
            msg.Body += "<td>Thanking</td><td>Team Budgetize</td>";
            msg.Body += "</tr>";
            #endregion

            string toAddress = email; // Add Recepient address
            msg.To.Add(toAddress);
            string fromAddress = "\"Budgetize \" <[email protected]>";
            msg.From = new MailAddress(fromAddress);
            msg.IsBodyHtml = true;

            try {smtp.Send(msg);}
            catch (Exception ex) {throw;}
        }
    }
}

Deepak Jha Deepak Jha · Accepted Answer · 2017-02-22T13:32:14

The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required.

ASP.NET using gmail with smtp error: "A connection attempt failed because the connected party did not properly respond.."

2 Answers