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

Question

i want to send email using this code but there is the problem appear so how can i solve this issue

<asp:TextBox ID="To"  runat="server"></asp:TextBox><br />
            <asp:TextBox ID="from" runat="server"></asp:TextBox><br />
                      <asp:TextBox ID="subject" runat="server"></asp:TextBox><br />
                      <asp:TextBox ID="body" runat="server"></asp:TextBox><br />
                      <asp:Button ID="Button3" OnClick="send" runat="server" Text="send" />


 protected void send(object sender, EventArgs e)
    {
        MailMessage message = new MailMessage(To.Text,from.Text,subject.Text,body.Text);
        message.IsBodyHtml = true;
        SmtpClient client = new SmtpClient("smtp.gmail.com", 587);
        client.EnableSsl = true;

        client.Credentials = new System.Net.NetworkCredential("email","pass");
        client.Send(message);


    }



at System.Net.Mail.MailCommand.CheckResponse(SmtpStatusCode statusCode, String response) at System.Net.Mail.MailCommand.Send(SmtpConnection conn, Byte[] command, MailAddress from, Boolean allowUnicode) at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, Boolean allowUnicode, SmtpFailedRecipientException& exception) at System.Net.Mail.SmtpClient.Send(MailMessage message) at AmbulanceManagementSystem.Front_End_Paramedics.SavePatientInfo.send(Object sender, EventArgs e) in c:\Users\Zoulfikar\Documents\Visual Studio 2013\Projects\AmbulanceManagementSystem\AmbulanceManagementSystem\Front End Paramedics\SavePatientInfo.aspx.cs:line 161

Answer 1

I just ran into the same problem, you have to turn on "less secure access". You should have an email in your inbox stating this, assuming the password is correct. Here is the code I'm using that works.

public void SendEmail(string address, string attatchment)
    {
        using (MailMessage mail = new MailMessage())
        {
            mail.From = new MailAddress("FromEmail@gmail.com");
            mail.To.Add("ToEmail@gmail.com");
            mail.Subject = "Report";
            mail.Body = "Report";
            mail.IsBodyHtml = true;
            mail.Attachments.Add(new Attachment(attatchment));

            using (SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587))
            {
                smtp.Credentials = new NetworkCredential("FromEmail@gmail.com", "Password");
                smtp.EnableSsl = true;
                smtp.Send(mail);
            }
        }
    }