Email Code Error

In Email co开发者_如何学编程de, I get following error.

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

Is this indicating that we require SSL certificate ?

This error code means that you need to provide a valid credentials in order to use this smtp server:

var client = new SmtpClient("smtp.gmail.com", 587);
client.EnableSsl = true;
client.Credentials = new NetworkCredential("youraccount@gmail.com", "secret");