Settings page does not work

Hi!

I just installed Qubely but the settings page shows an error.

Google MAP

There has been a critical error on this website. Please check your site admin email inbox for instructions.

In the logs I find an error like this:

PHP Fatal error: Uncaught Error: Class 'Fields' not found in /var/www/html/wp-content/plugins/qubely/core/admin-views/Settings.php:296\nStack trace:\n#0 /var/www/html/wp-includes/class-wp-hook.php(303): QUBELY_Settings->markup('')\n#1 /var/www/html/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters('', Array)\n#2 /var/www/html/wp-includes/plugin.php(470): WP_Hook->do_action(Array)\n#3 /var/www/html/wp-admin/admin.php(259): do_action('toplevel_page_q...')\n#4 {main}\n thrown in /var/www/html/wp-content/plugins/qubely/core/admin-views/Settings.php on line 296

The error was reproducible on a site without any plugin, on both WordPress 5.8.1 and WordPress 5.8.2.

Hope that helps?

Best,
Helmuth