Fatal error: Uncaught Error: Call to undefined function is_plugin_active() in /home/jamcodes/www/blog.a-tempo.co.jp/wp-content/plugins/rich-table-of-content/functions.php:519 Stack trace: #0 /home/jamcodes/www/blog.a-tempo.co.jp/wp-content/plugins/rich-table-of-content/functions.php(653): rtoc_get_index('\n<p>\xE3\x81\xA9\xE3\x81\x86\xE3\x82\x82\xE3\x81...') #1 /home/jamcodes/www/blog.a-tempo.co.jp/wp-includes/class-wp-hook.php(308): rtoc_switch_mokuji('\n<p>\xE3\x81\xA9\xE3\x81\x86\xE3\x82\x82\xE3\x81...') #2 /home/jamcodes/www/blog.a-tempo.co.jp/wp-includes/plugin.php(205): WP_Hook->apply_filters('\n<p>\xE3\x81\xA9\xE3\x81\x86\xE3\x82\x82\xE3\x81...', Array) #3 /home/jamcodes/www/blog.a-tempo.co.jp/wp-includes/post-template.php(255): apply_filters('the_content', '<!-- wp:paragra...') #4 /home/jamcodes/www/blog.a-tempo.co.jp/wp-content/themes/mag_tcd036-child/single.php(46): the_content('\xE8\xA9\xB3\xE7\xB4\xB0\xE3\x82\x92\xE8\xA6\x8B\xE3\x82\x8B') #5 /home/jamcodes/www/blog.a-tempo.co.jp/wp-includes/template-loader.php in /home/jamcodes/www/blog.a-tempo.co.jp/wp-content/plugins/rich-table-of-content/functions.php on line 519