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

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

I have a problem when i m run this code then error is occured that "The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. "

And my code is:

Code

protected void ImageButton1_Click(object sender, ImageClickEventArgs e)
{

    MailMessage mail = new MailMessage();
    mail.To.Add("info@msslindia.com");
    mail.From = new MailAddress("info@msslindia.com");
    string body = "<table><tr><td>Company Name:</td><td>" + txt_cname.Text + "</td></tr><tr><td>Address With No.:</td><td>" + txt_addwithno.Text + "</td></tr><tr><td>Contact Person:</td><td>" + txt_conperson.Text + "</td></tr><tr><td>Email Id</td><td>" + txt_email.Text + "</td></tr><tr><td>Description</td><td>" + txt_description.Text + "</td></tr></table>";
    mail.Body = body;
    mail.IsBodyHtml = true;
    SmtpClient smtp = new SmtpClient();
    smtp.Host = "smtp.gmail.com";
    smtp.Port = 587;

    smtp.Credentials = new System.Net.NetworkCredential("info@msslindia.com", "12345");
    smtp.EnableSsl = true;
    smtp.Send(mail);


    txt_cname.Focus();
    txt_cname.Text = "";
    txt_addwithno.Text = "";
    txt_conperson.Text = "";
    txt_email.Text = "";
    txt_description.Text = "";

}

Are you sure the username and password are correct? (obvious thing to check first!) Try logging into Gmail via their website, using exactly the same username/password combo. — Bridge, May 22 '12 at 09:30
I faced same issue so I went to gmail and login so I found captcha I filled it up and run my code and it works.lets try. — PrateekSaluja, Nov 23 '12 at 08:55

score 10 · Answer 1 · answered Oct 30 '12 at 10:30

10

Where are you hosting your website? Gmail prevents unrecognized access to your accounts. Try to execute this code and then go to you gmail and it will ask you if the access try was from you. Allow the application and you are done.

answered Oct 30 '12 at 10:30

Magnus

101
1
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The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required.

1 Answers1