The SMTP server requires a secure connection or the client was not authenticated. -.

Question

Hello
I wrote this code. I searched but could not find a solution for my problem.
private void button_sendemail_Click(object sender, EventArgs e)
string temp = "mygmailpassword";
System.Security.SecureString password = new System.Security.SecureString();
temp.ToCharArray().ToList().ForEach(p => password.AppendChar(p));
string mailfrom = "…@gmail.com";
string mailto = "…@yahoo.com";
string subject = "Hello";
string body = "Hello, I'm just writing this to say Hi!";
using (MailMessage mail = new MailMessage())
mail.From = new MailAddress(mailfrom);
mail.To.Add(mailto);
mail.Subject = subject;
mail.Body = body;
mail.IsBodyHtml = true;
// Can set to false, if you are sending pure text.
using (SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587))
smtp.UseDefaultCredentials = false;
smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
smtp.Credentials = new NetworkCredential(mailfrom, password);
smtp.EnableSsl = true;
smtp.Send(mail);

Answer 1

Hi ARZARE,
After some research and i have tested your code, it works fine on my side. But i used Hotmail
using (SmtpClient smtp = new SmtpClient("smtp.live.com", 587))
Per my understanding, you're trying to send from an @gmail.com address and they will require authentication, but you don't have credentials specified.  Try sending from @hotmail.com or change smtp.EnableSsl
= false to see what happens.
Best regards,
Kristin
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