How to code my website to download files from a file sharing site

I have two large files that I want to make available for users to download. When trying to download from my web host, the download never starts and I get a "504 Gateway Timeout". How would I revise my code to download from a file sharing site? I tried the following code but get a "This page isnt workingfoxclone is currently unable to handle this request."

Appreciate any help you can provide.

<?php

function mydloader($l_filename=NULL) {

    $php_scripts = '../../php/';
    require $php_scripts . 'PDO_Connection_Select.php';
    require $php_scripts . 'GetUserIpAddr.php';

    if( isset( $l_filename ) ) { 

       if substr($l_filename, 0, 10)=='foxclone_s' {
            $url_path = 'https://www.mediafire.com/file/tyqr4tzthiftuy1/foxclone_std-50-06.iso/file' }
       elseif substr($l_filename, 0, 10)=='foxclone_e' {
          $url_path = 'https://www.mediafire.com/file/xnovs5ltdj2z5wr/foxclone_edge-50-07.iso/file'  }
      else

              header('Content-Type: application/octet-stream');
              header("Content-Transfer-Encoding: Binary"); 
              header("Content-disposition: attachment"); 
              header('Pragma: no-cache');
              header('Expires: 0');       
              readfile($l_filename);
    }


        $ip = GetUserIpAddr();
        if (!$pdo = PDOConnect("foxclone_data"))
        {   echo "unable to connect";
            exit;
        }


        $test = $pdo->query("SELECT lookup.id FROM lookup WHERE inet_aton('$ip') >= lookup.ipstart AND inet_aton('$ip') <= lookup.ipend");
        $ref = $test->fetchColumn();
        $ref = intval($ref);

        $ext = pathinfo($l_filename, PATHINFO_EXTENSION);
        $stmt = $pdo->prepare("INSERT INTO download (address, filename, ip_address, lookup_id) VALUES (?, ?, inet_aton('$ip'), ?)");
        $stmt->execute([$ip, $ext, $ref ]) ; 

       }

    else {
        echo "isset failed";
        }  
}
mydloader($_GET["f"]);