hi am geting this error Failure sending mail. pls help me

my code is

try

{

//Mail Message

MailMessage mM = new MailMessage();

mM.From = new MailAddress("[email protected]");

//receiver email id

mM.To.Add("[email protected]");

mM.Subject = "Text H2H Mail";

File.Copy("D:\\ClientMgmtDb1.accdb", "D:\\ClientMgmtDb21.accdb", true);

mM.Attachments.Add(new Attachment(@"D:\\ClientMgmtDb21.accdb"));

mM.Body = "Log_Fole";

mM.IsBodyHtml = true;

// SmtpClient sC = new SmtpClient("smtp.WorldClient.com");

SmtpClient sC = new SmtpClient("192.168.100.10");

// SmtpClient.UseDefaultCredentials = true;

sC.Port = 25;

sC.Credentials = new NetworkCredential("[email protected]", "pintoo@123");

sC.EnableSsl = false;

sC.Send(mM);

MessageBox.Show("Mail send Successfully..Thanks");

mM.Dispose();

File.Delete("D:\\ClientMgmtDb21.accdb");

}

catch (Exception ex)

{

MessageBox.Show("Error" + ex.Message.ToString());

}