Programmatically download a shared file using C++ Curl

Below is the code I use:

#include "Stdafx.h"
#include "curl.h"
#include "Download.h"

static const char* FileURL[] = {
"https://www.dropbox.com/s/9thz78bwfeykqra/version.dat?dl=0" ,
"https://www.dropbox.com/s/9thz78bwfeykqra/version.dat?dl=1"
} ;

static size_t write_data (void *ptr,size_t size,size_t nmemb,void* stream)
{
size_t written = fwrite (ptr,size,nmemb,(FILE * ) stream) ;
return written ;
}

int DownloadFile ()
{
static char TargetURL[] = "E:\\Download\\DownloadURL\\Test.dat" ;
static char TargetCURL[] = "E:\\Download\\DownloadCURL\\Test.dat" ;

// Download the file using windows function into DownloadURL folder
URLDownloadToFile (nullptr,FileURL[1],TargetURL,0,nullptr) ;

// Download the file using curl library into DownloadCURL folder
if (auto curl = curl_easy_init ()) {
auto fp = fopen (TargetCURL,"wb") ;
curl_easy_setopt (curl,CURLOPT_URL,FileURL[1]) ;
curl_easy_setopt (curl,CURLOPT_WRITEFUNCTION,write_data) ;
curl_easy_setopt (curl,CURLOPT_FOLLOWLOCATION,1) ;
curl_easy_setopt (curl,CURLOPT_FAILONERROR,1) ;
curl_easy_setopt (curl,CURLOPT_WRITEDATA,fp) ;
curl_easy_setopt (curl,CURLOPT_HTTPPROXYTUNNEL,1) ;

/* Perform the request, res will get the return code */
auto res = curl_easy_perform (curl) ;

fclose (fp) ;
curl_easy_cleanup (curl) ;
} /* if (auto curl = curl_easy_init ()) */

return true ;

} /* Download */

The original link is FileURL[0] and the modified link is FileURL[1]

The downloaded file with Curl library, and original link, is an html the opens a web page for downloading the file. If I typed the shared link into the address bar in my browser, I get same page.

When I download the modified link, both windows function and Curl library download nothing. Curl function curl_easy_perform () returns : (6) CURL_COULDNT_RESOLVE_HOST.

would you like to inspect the html files I get with original link, Because they may have some information that I can not read.

Thank for your help.