Fatal error: Uncaught Error: Call to undefined function add_action() in /home/users/0/ryota/web/volf/wp-includes/functions.php:5391 Stack trace: #0 /home/users/0/ryota/web/volf/wp-settings.php(81): require() #1 /home/users/0/ryota/web/volf/wp-config.php(93): require_once('/home/users/0/r...') #2 /home/users/0/ryota/web/volf/wp-load.php(37): require_once('/home/users/0/r...') #3 /home/users/0/ryota/web/volf/wp-blog-header.php(13): require_once('/home/users/0/r...') #4 /home/users/0/ryota/web/volf/index.php(22): require('/home/users/0/r...') #5 {main} thrown in /home/users/0/ryota/web/volf/wp-includes/functions.php on line 5391