Fatal error: Uncaught Error: Call to undefined function add_action() in /home/kacperg/public_html/kacpergr/wp-content/plugins/jetpack/modules/related-posts.php:38 Stack trace: #0 /home/kacperg/public_html/kacpergr/wp-content/plugins/jetpack/modules/related-posts.php(27): Jetpack_RelatedPosts_Module->__construct() #1 /home/kacperg/public_html/kacpergr/wp-content/plugins/jetpack/modules/related-posts.php(63): Jetpack_RelatedPosts_Module::instance() #2 {main} thrown in /home/kacperg/public_html/kacpergr/wp-content/plugins/jetpack/modules/related-posts.php on line 38