insufficient system storage.The server response was: Too many emails per connection

im sending mail to one admin address and one mail sending to that person who entered details saying "thanks for contacting us." in second mail/receipent mail sending its getting error."insufficient system storage.The server response was: Too many emails per connection" in second method "SendConfirmationMail" its giving error. too many mails

  private void SendMail()
        {
            System.IO.StringWriter sw = new System.IO.StringWriter();
            HtmlTextWriter hw = new HtmlTextWriter(sw);
            System.IO.StreamReader r = null;
            r = new System.IO.StreamReader(Server.MapPath("~/ContactMail.txt"));
            string body = r.ReadToEnd();
            MailMessage mail = new MailMessage();
            mail.To.Add(new MailAddress("srinivas@gmail.com"));
            mail.Body = body;
            mail.IsBodyHtml = true;
            //replacing txt file with dynamic content
            body = body.Replace("<%Name%>", Name);
            body = body.Replace("<%email%>", email);
            body = body.Replace("<%message%>", message);
            mail.Subject = "Applying For job";
            mail.Body = body;
            mail.IsBodyHtml = true;
            SmtpClient MailServer = new SmtpClient();
            MailServer.Send(mail);
            ScriptManager.RegisterClientScriptBlock(Page, typeof(Page), "clentscript", "alert('Thank u for contacting us..');", true);

        }
        private void SendConfirmationMail()
        {
            System.IO.StringWriter sw = new System.IO.StringWriter();
            HtmlTextWriter hw = new HtmlTextWriter(sw);
            MailMessage mail = new MailMessage();
            mail.To.Add(new MailAddress(email));
            mail.Body = "Thank u for contacting us...";
            mail.IsBodyHtml = true;
            mail.Subject = "Thank you Mail";
            mail.IsBodyHtml = true;
            SmtpClient MailServer = new SmtpClient();
            MailServer.Send(mail);
            ScriptManager.RegisterClientScriptBlock(Page, typeof(Page), "clentscript", "alert('Thank u for contacting us..');", true);
    }