Fatal error: Uncaught Error: Call to a member function getDisplayName() on null in /var/www/ojs3/lib/pkp/classes/i18n/Locale.php:279 Stack trace: #0 [internal function]: PKP\i18n\Locale->PKP\i18n\{closure}() #1 /var/www/ojs3/lib/pkp/classes/i18n/Locale.php(279): array_map() #2 /var/www/ojs3/lib/pkp/classes/i18n/Locale.php(271): PKP\i18n\Locale->getSupportedLocales() #3 /var/www/ojs3/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Support/Facades/Facade.php(338): PKP\i18n\Locale->getSupportedFormLocales() #4 /var/www/ojs3/lib/pkp/classes/form/Form.php(85): Illuminate\Support\Facades\Facade::__callStatic() #5 /var/www/ojs3/lib/pkp/classes/user/form/RegistrationForm.php(56): PKP\form\Form->__construct() #6 /var/www/ojs3/lib/pkp/pages/user/RegistrationHandler.php(62): PKP\user\form\RegistrationForm->__construct() #7 [internal function]: PKP\pages\user\RegistrationHandler->register() #8 /var/www/ojs3/lib/pkp/classes/core/PKPRouter.php(334): call_user_func() #9 /var/www/ojs3/lib/pkp/classes/core/PKPPageRouter.php(277): PKP\core\PKPRouter->_authorizeInitializeAndCallRequest() #10 /var/www/ojs3/lib/pkp/classes/core/Dispatcher.php(165): PKP\core\PKPPageRouter->route() #11 /var/www/ojs3/lib/pkp/classes/core/PKPApplication.php(388): PKP\core\Dispatcher->dispatch() #12 /var/www/ojs3/index.php(20): PKP\core\PKPApplication->execute() #13 {main} thrown in /var/www/ojs3/lib/pkp/classes/i18n/Locale.php on line 279