Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, function "wp_system_query_script" not found or invalid function name in /var/www/wptbox/wp-includes/class-wp-hook.php:324 Stack trace: #0 /var/www/wptbox/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters() #1 /var/www/wptbox/wp-includes/plugin.php(531): WP_Hook->do_action() #2 /var/www/wptbox/wp-includes/general-template.php(3133): do_action() #3 /var/www/wptbox/wp-content/themes/Newspaper/header.php(17): wp_body_open() #4 /var/www/wptbox/wp-includes/template.php(810): require_once('...') #5 /var/www/wptbox/wp-includes/template.php(745): load_template() #6 /var/www/wptbox/wp-includes/general-template.php(48): locate_template() #7 /var/www/wptbox/wp-content/themes/Newspaper/single.php(1): get_header() #8 /var/www/wptbox/wp-includes/template-loader.php(106): include('...') #9 /var/www/wptbox/wp-blog-header.php(19): require_once('...') #10 /var/www/wptbox/index.php(1): require('...') #11 {main} thrown in /var/www/wptbox/wp-includes/class-wp-hook.php on line 324