Fatal error: Uncaught Error: Call to undefined function add_action() in /home/k1818436/public_html/wp-content/plugins/pdf-viewer-for-wordpress/update-notifier.php:46 Stack trace: #0 {main} thrown in /home/k1818436/public_html/wp-content/plugins/pdf-viewer-for-wordpress/update-notifier.php on line 46