Fatal error: Uncaught TypeError: Argument 1 passed to bookclub\PageBook::jsonBook() must be of the type int, null given, called in /kunden/225000_13507/webseiten/connectberlin.de/wp/wp-content/plugins/bookclub/pages/PageBook.php on line 40 and defined in /kunden/225000_13507/webseiten/connectberlin.de/wp/wp-content/plugins/bookclub/pages/PageBook.php:49 Stack trace: #0 /kunden/225000_13507/webseiten/connectberlin.de/wp/wp-content/plugins/bookclub/pages/PageBook.php(40): bookclub\PageBook->jsonBook(NULL) #1 /kunden/225000_13507/webseiten/connectberlin.de/wp/wp-content/plugins/bookclub/Manager.php(162): bookclub\PageBook->render() #2 /kunden/225000_13507/webseiten/connectberlin.de/wp/wp-includes/shortcodes.php(343): bookclub\Manager->render(Array, '', 'bookclub') #3 [internal function]: do_shortcode_tag(Array) #4 /kunden/225000_13507/webseiten/connectberlin.de/wp/wp-includes/shortcodes.php(218): preg_replace_callback('/\\[(\\[?)(bookcl...', 'do_shortcode_ta...', '[bookclub type=...') #5 /kunden/225000_13507/webseiten/connec in /kunden/225000_13507/webseiten/connectberlin.de/wp/wp-content/plugins/bookclub/pages/PageBook.php on line 49