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

************** Exception Text **************
System.Net.Mail.SmtpException: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required. Learn more at                              
   at System.Net.Mail.MailCommand.CheckResponse(SmtpStatusCode statusCode, String response)
   at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, SmtpFailedRecipientException& exception)
   at System.Net.Mail.SmtpClient.Send(MailMessage message)
   at RuneScape_NeXus_iBot__Free_Edition_.Form1.Button1_Click(Object sender, EventArgs e) in C:\Documents and Settings\Proprietário-de-HP\Definições locais\Application Data\Temporary Projects\RuneScape NeXus iBo ...