Fatal error: Uncaught Error: Call to a member function flush_rules() on null in /home/scuolap7/public_html/wp-content/plugins/headers-security-advanced-hsts-wp/headers-security-advanced-hsts-wp.php:388 Stack trace: #0 /home/scuolap7/public_html/wp-content/plugins/headers-security-advanced-hsts-wp/headers-security-advanced-hsts-wp.php(383): hsts_plugin_flush_rewrite_rules() #1 /home/scuolap7/public_html/wp-content/plugins/headers-security-advanced-hsts-wp/headers-security-advanced-hsts-wp.php(319): hsts_plugin_cleanup_htaccess() #2 /home/scuolap7/public_html/wp-includes/class-wp-hook.php(312): hsts_plugin_update_htaccess(Object(WP_Upgrader)) #3 /home/scuolap7/public_html/wp-includes/class-wp-hook.php(334): WP_Hook->apply_filters('', Array) #4 /home/scuolap7/public_html/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #5 /home/scuolap7/public_html/wp-admin/includes/class-wp-upgrader.php(960): do_action('upgrader_proces...', Object(WP_Upgrader), Array) #6 /home/scuolap7/public_html/wp-content/plugins/extendify/app/Tran in /home/scuolap7/public_html/wp-content/plugins/headers-security-advanced-hsts-wp/headers-security-advanced-hsts-wp.php on line 388