Fatal error: Uncaught Error: Class "WP_Customize_Section" not found in C:\xampp\htdocs\alumni-rmutr\wp-includes\customize\class-wp-customize-sidebar-section.php:17 Stack trace: #0 {main} thrown in C:\xampp\htdocs\alumni-rmutr\wp-includes\customize\class-wp-customize-sidebar-section.php on line 17