I got error as The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.1 Client was not authenticated

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Hi Team,

Here is my code. While iam executing this got the below error. Please anyone help on this issue.

Error"The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.1 Client was not authenticated "

Code:

C#

System.Net.Mail.MailMessage message = new System.Net.Mail.MailMessage();
               SmtpClient smtpClient = new SmtpClient();
               MailAddress fromAddress = new MailAddress(From, displayName);
                          message.From = fromAddress;
               message.Subject = "Test Mail in SMTP";
               message.To.Add(To);
               smtpClient.Host = "smtp";
               smtpClient.Port = 25;
               smtpClient.UseDefaultCredentials = false;
               smtpClient.Credentials = new System.Net.NetworkCredential("Mail", "pwd");
               //smtpClient.EnableSsl = true;
               System.Net.NetworkCredential auth = new System.Net.NetworkCredential("Mail", "pwd");
               smtpClient.Credentials = auth;
               smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;
               smtpClient.Send(message);

Posted 18-Feb-15 21:11pm

v2vinoth

Updated 18-Feb-15 21:24pm

RajeeshMenoth

v2

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3 solutions

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Imran Developer · Answer 1 · 2015-02-18T21:28:00

C#

using System;
using System.Windows.Forms;
using System.Net.Mail;

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                MailMessage mail = new MailMessage();
                SmtpClient SmtpServer = new SmtpClient("smtp.gmail.com");

                mail.From = new MailAddress("your_email_address@gmail.com");
                mail.To.Add("to_address");
                mail.Subject = "Test Mail";
                mail.Body = "This is for testing SMTP mail from GMAIL";

                SmtpServer.Port = 587;
                SmtpServer.Credentials = new System.Net.NetworkCredential("username", "password");
                SmtpServer.EnableSsl = true;

                SmtpServer.Send(mail);
                MessageBox.Show("mail Send");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
        }
    }
}

Namith Krishnan E · Answer 2 · 2015-02-19T00:51:00

Solution 3

The error says either your username or passwoord is incorrect,or enable the ssl

Posted 19-Feb-15 0:51am

Namith Krishnan E

RajeeshMenoth · Answer 3 · 2015-02-18T21:30:00

Use this code...

C#

using System.IO;
using System.Net;
using System.Net.Mail;
using System.Text;
using System.Globalization;

string to = "rajeeshmenoth@wordpress.com";//To address
string from = "rajeeshmenoth@wordpress.com";//From address
MailMessage message = new MailMessage(from, to);

if (fuAttachment.HasFile)//Attaching document
        {
            string FileName = Path.GetFileName(fuAttachment.PostedFile.FileName);
            message .Attachments.Add(new Attachment(fuAttachment.PostedFile.InputStream, FileName));
        }
message.Subject = txt_subject.text;
message.Body = mailbody;
message.BodyEncoding = Encoding.UTF8;
message.IsBodyHtml = true;
SmtpClient client = new SmtpClient("smtp.gmail.com", 587);
System.Net.NetworkCredential basicCredential1 = new
System.Net.NetworkCredential("yourmail id", "Password");
client.EnableSsl = true;
client.UseDefaultCredentials = false;
client.Credentials = basicCredential1;
try
{
client.Send(message);
}
catch (Exception ex)
{
throw ex;
}

or

HTML

smtpClient.EnableSsl = true;//enable the ssl

I got error as The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.1 Client was not authenticated

3 solutions

Solution 1

Solution 3

Solution 2

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