Fatal error: Uncaught Error: Call to undefined function is_plugin_active() in /home/sisco/tweevents.com/public_html/wp-content/plugins/rich-table-of-content/functions.php:519
Stack trace:
#0 /home/sisco/tweevents.com/public_html/wp-content/plugins/rich-table-of-content/functions.php(653): rtoc_get_index('<p>4\xE3\x82\xAB\xE6\x9C\x88\xE3\x81\xBB\xE3\x81...')
#1 /home/sisco/tweevents.com/public_html/wp-includes/class-wp-hook.php(324): rtoc_switch_mokuji('<p>4\xE3\x82\xAB\xE6\x9C\x88\xE3\x81\xBB\xE3\x81...')
#2 /home/sisco/tweevents.com/public_html/wp-includes/plugin.php(205): WP_Hook->apply_filters('<p>4\xE3\x82\xAB\xE6\x9C\x88\xE3\x81\xBB\xE3\x81...', Array)
#3 /home/sisco/tweevents.com/public_html/wp-includes/formatting.php(3965): apply_filters('the_content', '\r\n\r\n4\xE3\x82\xAB\xE6\x9C\x88\xE3\x81\xBB\xE3...')
#4 /home/sisco/tweevents.com/public_html/wp-includes/class-wp-hook.php(324): wp_trim_excerpt('\r\n\r\n4\xE3\x82\xAB\xE6\x9C\x88\xE3\x81\xBB\xE3...', Object(WP_Post))
#5 /home/sisco/tweevents.com/public_html/wp-includes/plugin.php(205): WP_Hook->apply_filters('', Array)
#6 /home/sisco/tweevents.com/public_html/wp-includes/post-template.php(436): apply_filters('get_the_excerpt', '', Object(WP_Post))
#7 /home/sisco/tweevents.com/public_html/wp-content/themes/sango-theme/library/functions/head.php(130): get_the_excerpt()
#8 /home/sisco/tweevents.com/public_html/wp-content/themes/sango-theme/library/functions/head.php(201): sng_set_ogp_description()
#9 /home/sisco/tweevents.com/public_html/wp-includes/class-wp-hook.php(324): sng_meta_ogp('')
#10 /home/sisco/tweevents.com/public_html/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters(NULL, Array)
#11 /home/sisco/tweevents.com/public_html/wp-includes/plugin.php(517): WP_Hook->do_action(Array)
#12 /home/sisco/tweevents.com/public_html/wp-includes/general-template.php(3064): do_action('wp_head')
#13 /home/sisco/tweevents.com/public_html/wp-content/themes/sango-theme/header.php(12): wp_head()
#14 /home/sisco/tweevents.com/public_html/wp-includes/template.php(810): require_once('/home/sisco/twe...')
#15 /home/sisco/tweevents.com/public_html/wp-includes/template.php(745): load_template('/home/sisco/twe...', true, Array)
#16 /home/sisco/tweevents.com/public_html/wp-includes/general-template.php(48): locate_template(Array, true, true, Array)
#17 /home/sisco/tweevents.com/public_html/wp-content/themes/sango-theme/single.php(1): get_header()
#18 /home/sisco/tweevents.com/public_html/wp-includes/template-loader.php(106): include('/home/sisco/twe...')
#19 /home/sisco/tweevents.com/public_html/wp-blog-header.php(19): require_once('/home/sisco/twe...')
#20 /home/sisco/tweevents.com/public_html/index.php(17): require('/home/sisco/twe...')
#21 {main}
thrown in /home/sisco/tweevents.com/public_html/wp-content/plugins/rich-table-of-content/functions.php on line 519