Fatal error: Uncaught Error: Call to undefined function add_shortcode() in C:\xampp\htdocs\wp-content\plugins\wp-timelines\shortcode\timeline-hozizontal.php:163 Stack trace: #0 {main} thrown in C:\xampp\htdocs\wp-content\plugins\wp-timelines\shortcode\timeline-hozizontal.php on line 163