public static bool sendMail(string strTo, string strSubject, string strName, string strbody)
    {
        try
        {
            strName = strName == "" ? "Sir/Madam" : ("Dear " + strName + ",");
            StringBuilder mailbody = new StringBuilder();
            SmtpClient mailClient = null;
            MailMessage message = null;
            mailClient = new SmtpClient();
            message = new MailMessage();

            mailClient.Host = ConfigurationManager.AppSettings["SMTP_MAIL_SERVER"];
            mailClient.Port = int.Parse(ConfigurationManager.AppSettings["PORT"]);
            //network credentials
            string strMailUserName = ConfigurationManager.AppSettings["FROM_ADDR"];
            string strMailPassword = ConfigurationManager.AppSettings["FROM_ADDR_PASS"];
            string strWebSiteURL = ConfigurationManager.AppSettings["LinkTosite"];

            mailClient.EnableSsl = true;
            System.Net.NetworkCredential SMTPUserInfo = new System.Net.NetworkCredential(strMailUserName, strMailPassword);
            mailClient.UseDefaultCredentials = true;
            mailClient.Credentials = SMTPUserInfo;

            string strFromMail = ConfigurationManager.AppSettings["FROM_ADDR"];
            MailAddress fromAddress = new MailAddress(strFromMail, "TEST (Administrator)");
            message.From = fromAddress;

            message.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure | DeliveryNotificationOptions.OnSuccess;

            //to mail address
            message.To.Add(strTo);
            message.Subject = "ChatOnGo : " + strSubject;

            //mailbody.AppendFormat("<link href='" + strWebSiteURL + "admin/css/bestlogin.css' rel='stylesheet' type='text/css' />");
            mailbody.AppendFormat("<div class='dlogin_bg'><div class='dlogin_bg_top'></div><div class='dlogin_bg_bottom'><h2>" + strName + "</h2>");
            mailbody.AppendFormat(strbody);
            mailbody.AppendFormat("<br/><br/><span>Regards,<br /><a href='" + strWebSiteURL + "'>ChatOnGo Admin</a></span></div></div>");

            message.Body = mailbody.ToString();
            message.IsBodyHtml = true;
            mailClient.SendMailAsync(message);


            message = null;
            mailClient = null;

            return true;
        }
        catch (SmtpFailedRecipientsException ep)
        {
            Console.WriteLine(ep.Message);
            return false;
        }
        catch (Exception ep)
        {
            Console.WriteLine(ep.Message);
            return false;
        }
    }