Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, function "wp_ob_end_flush_all" not found or invalid function name in /home/qbaytggk/public_html/wp-includes/class-wp-hook.php:324
Stack trace:
#0 /home/qbaytggk/public_html/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters('', Array)
#1 /home/qbaytggk/public_html/wp-includes/plugin.php(517): WP_Hook->do_action(Array)
#2 /home/qbaytggk/public_html/wp-includes/load.php(1270): do_action('shutdown')
#3 [internal function]: shutdown_action_hook()
#4 {main}
thrown in /home/qbaytggk/public_html/wp-includes/class-wp-hook.php on line 324