I am running DES in a window machine without internet. To that DES I integrated a custom DSS but when I try to upload any document on DSS, after redirecting to DES it displays an error message "Download failed". I explored a lot for its solution, did lots of trail-n-error practices but with no solution. So what might be the cause of it ? What's the solution ? I have attached a screenshot of error for more clarification of the error message.