PHP Export to CSV file works on XAMPP but not Hostgator

Question

this code works on my offline version in xampp and automatically downloads CSV file. But the same code doesn't work on my live website in Hostgator. Is there something that i should change? it just displays on the browser instead of automatically generating/downloading the csv file

    $delimiter = ","; 
    $filename = "depot_".$direction. date('Y-m-d') . ".csv"; 
 
    // Create a file pointer 
    $f = fopen('php://memory', 'w'); 
 
    // Set column headers 
    $fields = array( 'Depot Ref','Container No', 'Container Type', 'Check-In Date', 'Storage'); 
    fputcsv($f, $fields, $delimiter); 
 
    // Output each row of the data, format line as csv and write to file pointer 
    while($row = $stmt->fetch(PDO::FETCH_ASSOC))
    {                                                           

        $storage=getStorage($row["depotRef"]);
        $lineData = array( $row["depotRef"], $row['containerNo'], $row['containerType'], 
        $row['checkIn'], $storage); 
        fputcsv($f, $lineData, $delimiter); 



    }

 
    // Move back to beginning of file 
    fseek($f, 0); 
 
    // Set headers to download file rather than displayed 
    header('Content-Type: text/csv'); 
    header('Content-Disposition: attachment; filename="' . $filename . '";'); 
 
    //output all remaining data on a file pointer 
    fpassthru($f); 

exit;