How To Use SMTP with TLS

uses
  blcksock, smtpsend, pop3send, ssl_openssl,
//...
 
type
  ESMTP = class (Exception);
//...
 
// e-mail template (subject and other headers+CRLF+CRLF+e-mail body) 
// in file sFileName
procedure MailSend(const sSmtpHost, sSmtpPort, sSmtpUser, sSmtpPasswd, sFrom, sTo, sFileName: AnsiString);
var
  smtp: TSMTPSend;
  msg_lines: TStringList;
begin
  msg_lines := TStringList.Create;
  smtp := TSMTPSend.Create;
  try
    msg_lines.LoadFromFile(sFileName);
    msg_lines.Insert(0, 'From: ' + sFrom);
    msg_lines.Insert(1, 'To: ' + sTo);
 
    smtp.UserName := sSmtpUser;
    smtp.Password := sSmtpPasswd;
 
    smtp.TargetHost := sSmtpHost;
    smtp.TargetPort := sSmtpPort;
 
    AddToLog('SMTP Login');
    if not smtp.Login() then
      raise ESMTP.Create('SMTP ERROR: Login:' + smtp.EnhCodeString);
    AddToLog('SMTP StartTLS');
    if not smtp.StartTLS() then
      raise ESMTP.Create('SMTP ERROR: StartTLS:' + smtp.EnhCodeString);
 
    AddToLog('SMTP Mail');
    if not smtp.MailFrom(sFrom, Length(sFrom)) then
      raise ESMTP.Create('SMTP ERROR: MailFrom:' + smtp.EnhCodeString);
    if not smtp.MailTo(sTo) then
      raise ESMTP.Create('SMTP ERROR: MailTo:' + smtp.EnhCodeString);
    if not smtp.MailData(msg_lines) then
      raise ESMTP.Create('SMTP ERROR: MailData:' + smtp.EnhCodeString);
 
    AddToLog('SMTP Logout');
    if not smtp.Logout() then
      raise ESMTP.Create('SMTP ERROR: Logout:' + smtp.EnhCodeString);
    AddToLog('OK!');
  finally
    msg_lines.Free;
    smtp.Free;
  end;
end;