Fatal error: Uncaught Error: Call to a member function getId() on null in /var/www/vhosts/pen2print.org/journals.pen2print.org/lib/pkp/pages/notification/NotificationHandler.inc.php:155 Stack trace: #0 /var/www/vhosts/pen2print.org/journals.pen2print.org/lib/pkp/classes/core/PKPRouter.inc.php(362): NotificationHandler->getNotificationFeedUrl(Array, Object(Request)) #1 /var/www/vhosts/pen2print.org/journals.pen2print.org/lib/pkp/classes/core/PKPPageRouter.inc.php(220): PKPRouter->_authorizeInitializeAndCallRequest(Array, Object(Request), Array, false) #2 /var/www/vhosts/pen2print.org/journals.pen2print.org/lib/pkp/classes/core/Dispatcher.inc.php(134): PKPPageRouter->route(Object(Request)) #3 /var/www/vhosts/pen2print.org/journals.pen2print.org/lib/pkp/classes/core/PKPApplication.inc.php(178): Dispatcher->dispatch(Object(Request)) #4 /var/www/vhosts/pen2print.org/journals.pen2print.org/index.php(64): PKPApplication->execute() #5 {main} thrown in /var/www/vhosts/pen2print.org/journals.pen2print.org/lib/pkp/pages/notification/NotificationHandler.inc.php on line 155