Fatal error: Uncaught Error: Call to undefined function YoastSEO() in /var/app/current/wp-content/themes/otonano-shumatsu/functions.php:1638 Stack trace: #0 /var/app/current/wp-includes/class-wp-hook.php(303): setup_header('') #1 /var/app/current/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters(NULL, Array) #2 /var/app/current/wp-includes/plugin.php(470): WP_Hook->do_action(Array) #3 /var/app/current/wp-includes/general-template.php(3015): do_action('wp_head') #4 /var/app/current/wp-content/themes/otonano-shumatsu/header.php(40): wp_head() #5 /var/app/current/wp-includes/template.php(770): require_once('/var/app/curren...') #6 /var/app/current/wp-includes/template.php(716): load_template('/var/app/curren...', true, Array) #7 /var/app/current/wp-includes/general-template.php(48): locate_template(Array, true, true, Array) #8 /var/app/current/wp-content/themes/otonano-shumatsu/archive.php(9): get_header() #9 /var/app/current/wp-includes/template-loader.php(106): include('/var/app/curren...') #10 /var/app/current/wp-blog-header.php(19): require_once('/var/app/curren...') #11 /var/app/current/index.php(17): require('/var/app/curren...') #12 {main} thrown in /var/app/current/wp-content/themes/otonano-shumatsu/functions.php on line 1638