Force Download with PHP - Server Configuration?

Question

I've searched alot for that and nothing works for me. The Problem is that the file got displayed in the Browser. It includes JSON, but is an .locx file (needed for an APP). No not my APP so i cant change that. I've tested so much variations of Content Types and Encodings, but nothing helped me out. That is my Code.

<?php
    function DownloadFile($file) {
        if(file_exists($file)) {
            header('Content-Description: File Transfer');
            header('Content-Type: application/octet-stream');
            header('Content-Disposition: attachment; filename='.basename($file));
            header('Content-Transfer-Encoding: binary');
            header('Expires: 0');
            header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
            header('Pragma: public');
            header('Content-Length: ' . filesize($file));
            ob_clean();
            flush();
            readfile($file);
            exit;
        }

    }

    DownloadFile('storage/3-3-2.locx');
?>

Thanks for reading!

// UPDATE

It works on another Server, and as written in the comments the Script works very well, but what i have to change in the server configuration that it works for me too?

Answer 1

It happens , while uploading the file.

While uploading the file encoding changed from utf8 to iso.