Fatal error: Uncaught TypeError: array_merge(): Argument #6 must be of type array, null given in /var/www/html/wp-includes/widgets.php:1346 Stack trace: #0 /var/www/html/wp-includes/widgets.php(1346): array_merge(Array, Array, Array, Array, Array, NULL, Array, Array, Array, Array, Array, Array) #1 /var/www/html/wp-includes/widgets.php(1291): retrieve_widgets(true) #2 /var/www/html/wp-includes/class-wp-hook.php(326): _wp_sidebars_changed('Responsive') #3 /var/www/html/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters(NULL, Array) #4 /var/www/html/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #5 /var/www/html/wp-includes/theme.php(3496): do_action('after_switch_th...', 'Responsive', Object(WP_Theme)) #6 /var/www/html/wp-includes/class-wp-hook.php(324): check_theme_switched('') #7 /var/www/html/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters(NULL, Array) #8 /var/www/html/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #9 /var/www/html/wp-settings.php(695): do_action('init') #10 /var/www/html/wp-config.php(101): require_once('/var/www/html/w...') #11 /var/www/html/wp-load.php(50): require_once('/var/www/html/w...') #12 /var/www/html/wp-blog-header.php(13): require_once('/var/www/html/w...') #13 /var/www/html/index.php(17): require('/var/www/html/w...') #14 {main} thrown in /var/www/html/wp-includes/widgets.php on line 1346