Fatal error: Uncaught TypeError: Argument 1 passed to Sokil\IsoCodes\Database\Countries::getByAlpha2() must be of the type string, null given, called in /var/www/kosmo33/pages/search/SearchHandler.inc.php on line 272 and defined in /var/www/kosmo33/lib/pkp/lib/vendor/sokil/php-isocodes/src/Database/Countries.php:42
Stack trace:
#0 /var/www/kosmo33/pages/search/SearchHandler.inc.php(272): Sokil\IsoCodes\Database\Countries->getByAlpha2(NULL)
#1 /var/www/kosmo33/lib/pkp/classes/core/PKPRouter.inc.php(395): SearchHandler->authors(Array, Object(Request))
#2 /var/www/kosmo33/lib/pkp/classes/core/PKPPageRouter.inc.php(246): PKPRouter->_authorizeInitializeAndCallRequest(Array, Object(Request), Array, false)
#3 /var/www/kosmo33/lib/pkp/classes/core/Dispatcher.inc.php(144): PKPPageRouter->route(Object(Request))
#4 /var/www/kosmo33/lib/pkp/classes/core/PKPApplication.inc.php(362): Dispatcher->dispatch(Object(Request))
#5 /var/www/kosmo33/index.php(68): PKPApplication->execute()
#6 {main}
thrown in /var/www/kosmo33/lib/pkp/lib/vendor/sokil/php-isocodes/src/Database/Countries.php on line 42