Fatal error: Uncaught Error: Call to undefined function trailingslashit() in C:\xampp\htdocs\wp-content\plugins\members\addons\members-role-hierarchy\addon.php:80 Stack trace: #0 C:\xampp\htdocs\wp-content\plugins\members\addons\members-role-hierarchy\addon.php(42): Members_Role_Hierarchy_Plugin->setup() #1 C:\xampp\htdocs\wp-content\plugins\members\addons\members-role-hierarchy\addon.php(117): Members_Role_Hierarchy_Plugin::get_instance() #2 {main} thrown in C:\xampp\htdocs\wp-content\plugins\members\addons\members-role-hierarchy\addon.php on line 80