Live Paypal Erorr

[beast2]

i usage PayPal in ASP.net,i tested in sandbox and everything was correct,but when i use live part i getting this error :\[quote\] This payment cannot be completed and your account has not been charged. Please contact your merchant for more information. We are not able to process your payment using your PayPal account at this time. Please return to the merchant's website and try using a different payment method (if available).\[/quote\]this is my webconfig\[code\] <add key="token" value="http://stackoverflow.com/questions/12662249/*************************"/> <add key="paypalemail" value="http://stackoverflow.com/questions/12662249/*************@gmail.com"/> <add key="PayPalSubmitUrl" value="https://www.paypal.com/cgi-bin/webscr"/> <add key="FailedURL" value="http://www.stockholmsbygg.net/Failed.aspx"/> <add key="SuccessURL" value="http://www.stockholmsbygg.net/FindOpenRequests.aspx"/> <add key="Notification" value="http://www.stockholmsbygg.net/Notification.aspx"/>\[/code\]and redirect to Paypal\[code\] public static string RedirectToPaypal(string invoiceNumber, string requestId, string userId, string customId, string itemName, string amount) { string redirecturl = ""; redirecturl += "https://www.paypal.com/cgi-bin/webscr?cmd=_xclick&business=" + ConfigurationManager.AppSettings["paypalemail"].ToString(); redirecturl += "&first_name=" + userId; redirecturl += "&item_name=" + itemName; redirecturl += "&amount=5.00"; redirecturl += "&quantity=1"; redirecturl += "&currency=SEK"; redirecturl += "&invoice=" + invoiceNumber; redirecturl += "&custom=" + requestId; redirecturl += "&on0=" + HttpContext.Current.Request.UserHostAddress; redirecturl += "&return=" + ConfigurationManager.AppSettings["SuccessURL"].ToString() + "?Type=ShowDetail"; redirecturl += "&cancel_return=" + ConfigurationManager.AppSettings["FailedURL"].ToString(); redirecturl += "&notify_url=" + ConfigurationManager.AppSettings["Notification"].ToString(); return redirecturl; }\[/code\]and this is evrything that i check after return from paypal to my address\[code\]if (Request.QueryString["cm"] != null) { const string authToken = "*********************************"; string txToken = Request.QueryString["tx"]; string query = "cmd=_notify-synch&tx=" + txToken + "&at=" + authToken; //const string strSandbox = "https://www.sandbox.paypal.com/cgi-bin/webscr"; string strSandbox = "https://www.paypal.com/cgi-bin/webscr"; var req = (HttpWebRequest)WebRequest.Create(strSandbox); req.Method = "POST"; req.ContentType = "application/x-www-form-urlencoded"; req.ContentLength = query.Length; var streamOut = new StreamWriter(req.GetRequestStream(), System.Text.Encoding.ASCII); streamOut.Write(query); streamOut.Close(); var streamIn = new StreamReader(req.GetResponse().GetResponseStream()); string strResponse = streamIn.ReadToEnd(); streamIn.Close(); var results = new Dictionary<string, string>(); if (strResponse != "") { var reader = new StringReader(strResponse); string line = reader.ReadLine(); if (line == "SUCCESS") { while ((line = reader.ReadLine()) != null) { results.Add(line.Split('=')[0], line.Split('=')[1]); } var userId = Convert.ToInt64(Session["UserID"]); var item = Convert.ToInt64(Request.QueryString["cm"]); context = new entities(); var existUser = context.Payments.Where(u => u.UserID == userId).ToList(); var existItem = existUser.Where(i => i.RequestID == item).ToList(); var paypalInvoice = results["invoice"]; var txn_id = results["txn_id"]; var sameInvoice = existItem.Where(i => i.invoice== paypalInvoice).FirstOrDefault(); if (sameInvoice != null) { var currentAmount = Request.QueryString["amt"]; var dbAmount = Convert.ToDecimal(sameInvoice.Amount).ToString(); var currentIp = HttpContext.Current.Request.UserHostAddress; if (dbAmount != null) { if (currentAmount == dbAmount) { if (currentIp == sameInvoice.IP) { sameInvoice.Status = true; sameInvoice.PaypalTX = txn_id; pnlSearch.Visible = false; pnlShowDetail.Visible = true; ShowDetail(Request.QueryString["cm"], true); btnBack.Visible = false; PrivateDetail.Visible = true; interested.Visible = false; context.SaveChanges(); } } } } } else if (line == "FAIL") { // Log for manual investigation Response.Write("Unable to retrive transaction detail"); } } else { //unknown error Response.Write("ERROR"); } }\[/code\]is there any problem ?and at the first time for test i payed money but nothing happen i mean invoice status still false it should be true when i payed!!!