Fatal error: Uncaught TypeError: Argument 1 passed to Sokil\IsoCodes\Database\Countries::getByAlpha2() must be of the type string, null given, called in C:\www\pages\search\SearchHandler.inc.php on line 272 and defined in C:\www\lib\pkp\lib\vendor\sokil\php-isocodes\src\Database\Countries.php:42
Stack trace:
#0 C:\www\pages\search\SearchHandler.inc.php(272): Sokil\IsoCodes\Database\Countries->getByAlpha2(NULL)
#1 C:\www\lib\pkp\classes\core\PKPRouter.inc.php(391): SearchHandler->authors(Array, Object(Request))
#2 C:\www\lib\pkp\classes\core\PKPPageRouter.inc.php(231): PKPRouter->_authorizeInitializeAndCallRequest(Array, Object(Request), Array, false)
#3 C:\www\lib\pkp\classes\core\Dispatcher.inc.php(143): PKPPageRouter->route(Object(Request))
#4 C:\www\lib\pkp\classes\core\PKPApplication.inc.php(279): Dispatcher->dispatch(Object(Request))
#5 C:\www\index.php(68): PKPApplication->execute()
#6 {main}
thrown in C:\www\lib\pkp\lib\vendor\sokil\php-isocodes\src\Database\Countries.php on line 42