Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, non-static method WPUW::register_terms() cannot be called statically in /users/kleiderkammer/www/wp-includes/class-wp-hook.php:324 Stack trace: #0 /users/kleiderkammer/www/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters(NULL, Array) #1 /users/kleiderkammer/www/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #2 /users/kleiderkammer/www/wp-settings.php(695): do_action('init') #3 /users/kleiderkammer/www/wp-config.php(96): require_once('/users/kleiderk...') #4 /users/kleiderkammer/www/wp-load.php(50): require_once('/users/kleiderk...') #5 /users/kleiderkammer/www/wp-blog-header.php(13): require_once('/users/kleiderk...') #6 /users/kleiderkammer/www/index.php(17): require('/users/kleiderk...') #7 {main} thrown in /users/kleiderkammer/www/wp-includes/class-wp-hook.php on line 324