Nginx www does not work

I really do not know why my nginx configuration does not work for www.

My configuration is:

server {
    listen 80;
    server_name postimg.cz www.postimg.cz;
    return 301 https://$server_name$request_uri;
}

server {
    listen 443;

    server_name postimg.cz;

    # SSL Configuration
    ssl_certificate /etc/letsencrypt/live/postimg.cz/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/postimg.cz/privkey.pem;
    ssl_session_cache shared:SSL:10m;
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers "ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GC>
    ssl_prefer_server_ciphers on;

    # See https://hstspreload.org/ before uncommenting the line below.
    # add_header Strict-Transport-Security "max-age=15768000; preload;";
    add_header X-Content-Type-Options nosniff;
    add_header X-XSS-Protection "1; mode=block";
    add_header X-Robots-Tag none;
    add_header Content-Security-Policy "frame-ancestors 'self'";
    add_header X-Frame-Options DENY;
    add_header Referrer-Policy same-origin;

    root /var/www/postimg.cz;

    # Disable access to sensitive application files
    location ~* (app|content|lib)/.*\.(po|php|lock|sql)$ {
        return 404;
    }
    location ~* composer\.json|composer\.lock|.gitignore$ {
        return 404;
    }
    location ~* /\.ht {
        return 404;
    }

    # Image not found replacement
    location ~* \.(jpe?g|png|gif|webp)$ {
        log_not_found off;
        error_page 404 /content/images/system/default/404.gif;
    }

    # CORS header (avoids font rendering issues)
    location ~* \.(ttf|ttc|otf|eot|woff|woff2|font.css|css|js)$ {
        add_header Access-Control-Allow-Origin "*";
    }

    # PHP front controller
    location / {
        index index.php;
        try_files $uri $uri/ /index.php$is_args$query_string;
    }

    # Single PHP-entrypoint (disables direct access to .php files)
    location ~* \.php$  {
        internal;
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/var/run/php/php7.4-fpm.sock;
    }
}

But when I go to http://www.postimg.cz it won't redirect to https://postimg.cz why is that? Can you help me with it?

Server: Ubuntu Server 20.04

EDIT // Tried also this, does not work either:

server {
    listen 80;
    server_name www.postimg.cz postimg.cz;
    return 301 https://$server_name$request_uri;
}

server {
    listen 443 ssl;
    server_name www.postimg.cz;
    ssl_certificate /etc/letsencrypt/live/www.postimg.cz/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/www.postimg.cz/privkey.pem;
    return 301 https://postimg.cz$request_uri;
}

server {
    listen 443 ssl;

    server_name postimg.cz;