Cross domain XMLHttpRequest in classic ASP

Question

My code is working fine till i migrate it to another server with firewall. After since, some part of my code is not working. Its seem to be the xmlhttp POST problem. Can someone point me to the right direction and how to determine if the firewall is the problem. My client insisted to me to use classic asp, so i cannot upgrade to .net.

Dim objHttp
SUBMIT_URL = "http://www.abc.com/confirm.asp"

Call Process()

 Public Sub Process()

  set objHttp = Server.CreateObject("Microsoft.XMLHTTP")

  'set the timeout values in milliseconds
  lResolve = 1 * 1000
  lConnect = 1 * 1000
  lSend  = 2 * 1000
  lReceive = 2 * 1000

  objHttp.open "POST", SUBMIT_URL, false
  objHttp.setRequestHeader "Content-type", "application/x-www-form-urlencoded"
  objHttp.Send str
  if err.number <> 0 then
   Response.Write "Error : " & err.Description
   err.Clear 
  end if

 End Sub