Email sending problem

Question

Hello sir 

 

 I am sending mail during I get error which I mention below.

 

 "Bad sequence of commands. The server response was: This mail server requires authentication when attempting to send to a non-local e-mail address. Please check your mail client settings or contact your administrator to verify that the domain or address is defined for this serve

 

And My code is:

 

System.Net.Mail.MailMessage message = new System.Net.Mail.MailMessage();

SmtpClient smtpClient = new SmtpClient();

string msg = string.Empty;

try

{

MailAddress fromAddress = new MailAddress(SenderEmail);

message.From = fromAddress;

message.To.Add(Email);

message.Subject = " Registration Details";

message.IsBodyHtml = true;

// message.Body = "Email ID is: " + Email;

message.Body = "Email ID is: ";

smtpClient.Host = HostName; 

smtpClient.Port = PortNumber; 

smtpClient.EnableSsl = false;

smtpClient.UseDefaultCredentials = false;

smtpClient.Credentials = new System.Net.NetworkCredential(UserName, Password);

smtpClient.Send(message);

}

catch (Exception ex)

{

}