I’m getting error “The SMTP server requires a secure connection or the client was not authenticated. The server response was: authentication required”

My code is
MailMessage mail = new MailMessage();

mail.To.Add(TextTo.Text);

mail.From = new MailAddress(TextFrom.Text);

mail.Subject = TextSbj.Text;

mail.Body = TextBody.Text;

SmtpClient smtp = new SmtpClient();

smtp.Host = “in.smtp.mail.yahoo.com “;
smtp.Port = 587;
//smtp.EnableSsl = true;
smtp.UseDefaultCredentials = false;

smtp.Credentials = new System.Net.NetworkCredential(“username”, “password”);

smtp.DeliveryMethod = SmtpDeliveryMethod.Network;

smtp.Send(mail);

anyone help
thanx

My problem is I have a grid on page where we have updatepanel. On the grid there is Edit link which take to next page. On the next page I update the record and clicked save button. After updating the record, I click back button. On that Back button I have written Javascript History.go back. but when I click on this page it does not retain its state. i.e. If on the grid I was on 6 page, when I click back of Next page then I am on the first page.

Update Panel and Javascript go back is not working in the same manner.

If i remove update panel my problem is resolved the state is maintained on the grid but the data in the grid is not refreshed.

Please help

how can i call my javascript method with parameters at the end of the request?

for example,

function DynamicPostBack(ControlId)
{
//method body
}

http://www.uploadify.com/forum/viewtopic.php?f=7&t=142