Fatal error: Uncaught Error: Class 'WP_REST_Controller' not found in /home/ignas/public_html/ignas/wp-content/plugins/ultimate-addons-for-gutenberg/lib/gutenberg-templates/inc/api/api-base.php:16 Stack trace: #0 {main} thrown in /home/ignas/public_html/ignas/wp-content/plugins/ultimate-addons-for-gutenberg/lib/gutenberg-templates/inc/api/api-base.php on line 16