send email fails

[fanor]

I want to send an email from a windows aplication using my yahoo account.
I got some help before but still it's not working.
The code is:
MailMessage msg;
MailAddress msender, receiver;

SmtpClient client;

msender = new MailAddress(tfrom.Text); // pa***@yahoo.com

receiver = new MailAddress(tto.Text);

msg = new MailMessage(msender,receiver);

msg.Subject = tsubject.Text;

msg.Body = @"this is a test";

client = new SmtpClient("smtp.mail.yahoo.com");

client.Credentials = new NetworkCredential("Pablo","mypassword");

try

{

client.Send(msg);

}

catch (Exception e1)

{

MessageBox.Show(e1.Message);

}

................

......................

It looks like the problem is with NetworkCredential, any help is very
apreciated.

TIA