Envoyer un Email avec TNMSMTP (Fastnet)

procedure TForm1.Button1Click(Sender: TObject);
begin
NMSMTP1.Host := 'mail.host.com';
NMSMTP1.UserID := 'username';
NMSMTP1.Connect;
NMSMTP1.PostMessage.FromAddress := 'webmaster@swissdelphicenter.ch';
NMSMTP1.PostMessage.ToAddress.Text := 'user@host.com';
NMSMTP1.PostMessage.Body.Text := 'This is the message';
NMSMTP1.PostMessage.Subject := 'Mail subject';
NMSMTP1.SendMail;
showmessage('Mail sent !');
end;