The remote certificate is invalid according to the validation procedure.

[C# Programming]

When i send mail above error occurred.
would anyone say:

code is below:

MailAddress SendFrom = new MailAddress("test@nibssolutions.net");

MailAddress SendTo = new MailAddress("rudro_aiub@yahoo.com");
MailMessage myMessage = new MailMessage(SendFrom, SendTo);

myMessage.Subject = "Subject";
myMessage.Body = "Body";


SmtpClient _smtpClient = new SmtpClient("mail.nibssolutions.net", 587);

_smtpClient.EnableSsl = true;
_smtpClient.Credentials = new System.Net.NetworkCredential("test@nibssolutions.net", "********");

_smtpClient.Send(myMessage);
//}
MessageBox.Show("Mail Sent...");