Http Authentication in PHP not working on new hosting [closed]

Moved my website to Siteground shared hosting and http authentication stopped working on their server.

        if (!isset($_SERVER['PHP_AUTH_USER'])) {
        header('WWW-Authenticate: Basic realm="huahin"');
        header('HTTP/1.0 401 Unauthorized');
        echo 'Unauthorized';
        exit;
    } else {
        if($_SERVER['PHP_AUTH_USER']!='mylogin'){
        header('WWW-Authenticate: Basic realm="huahin"');
        header('HTTP/1.0 401 Unauthorized');
    } else {
        if($_SERVER['PHP_AUTH_PW']!='mypassword'){
        header('WWW-Authenticate: Basic realm="huahin"');
        header('HTTP/1.0 401 Unauthorized');
        }
    }

        include('conf.php');

When loading page I am receiving “Unauthorized” message right away.

My htaccess currently looks like that:

<IfModule mod_headers.c>
    Header set Access-Control-Allow-Origin "*"
</IfModule>

I’ve tried solution from this topic but it skips authorization and loads content without it.

I am not a developer, just a user who is trying to make things work on a new hosting. Thank you in advance for your help.