Fatal error: Uncaught TypeError: Return value of secondary_title_add_shortcode_function_init() must be an instance of void, none returned in /home/customer/www/sleeptrackers.io/public_html/wp-content/plugins/secondary-title/includes/hooks.php:540
Stack trace:
#0 /home/customer/www/sleeptrackers.io/public_html/wp-includes/class-wp-hook.php(292): secondary_title_add_shortcode_function_init('')
#1 /home/customer/www/sleeptrackers.io/public_html/wp-includes/class-wp-hook.php(316): WP_Hook->apply_filters(NULL, Array)
#2 /home/customer/www/sleeptrackers.io/public_html/wp-includes/plugin.php(484): WP_Hook->do_action(Array)
#3 /home/customer/www/sleeptrackers.io/public_html/wp-settings.php(560): do_action('init')
#4 /home/customer/www/sleeptrackers.io/public_html/wp-config.php(90): require_once('/home/customer/...')
#5 /home/customer/www/sleeptrackers.io/public_html/wp-load.php(37): require_once('/home/customer/...')
#6 /home/customer/www/sleeptrackers.io/public_html/wp-blog-header.php(13): require_once('/home/customer/...')
#7 / in /home/customer/www/sleeptrackers.io/public_html/wp-content/plugins/secondary-title/includes/hooks.php on line 540