installation problem

Hello,

I'm installing new vanilla 3.3 on my server.

I have all pre-requisite.

But when i go on my domain I see this error

applications/dashboard/controllers/api/LocalesApiController.php

 99: 
100:         $populate = function (array &$row, array $locales) {
101:             $displayNames = [];
102:             foreach ($locales as $locale) {
103:                 $displayName = \Locale::getDisplayLanguage($row["localeKey"], $locale);
104: 
105:                 // Standardize capitalization
106:                 $displayName = mb_convert_case($displayName, MB_CASE_TITLE);
107: 

Backtrace:

[/var/www/vhosts/domain.com/httpdocs/forum/applications/dashboard/controllers/api/LocalesApiController.php:117] LocalesApiController->{closure}();
[/var/www/vhosts/pron.com/httpdocs/forum/applications/dashboard/controllers/api/LocalesApiController.php:45] LocalesApiController->expandDisplayNames();
[/var/www/vhosts/pron.com/httpdocs/forum/library/Vanilla/Models/LocalePreloadProvider.php:36] LocalesApiController->index();
[/var/www/vhosts/pron.com/httpdocs/forum/library/Vanilla/Web/JsInterpop/ReduxActionPreloadTrait.php:51] Vanilla\Models\LocalePreloadProvider->createActions();
[/var/www/vhosts/pron.com/httpdocs/forum/library/core/class.controller.php:1967] Gdn_Controller->getReduxActionsAsJsVariable();
[/var/www/vhosts/pron.com/httpdocs/forum/library/core/class.controller.php:1471] Gdn_Controller->renderMaster();
[/var/www/vhosts/pron.com/httpdocs/forum/library/core/class.pluggable.php:217] Gdn_Controller->xRender();
[/var/www/vhosts/pron.com/httpdocs/forum/applications/dashboard/controllers/class.setupcontroller.php:155] Gdn_Pluggable->__call();
[/var/www/vhosts/pron.com/httpdocs/forum/library/core/class.dispatcher.php:872] SetupController->index();
[/var/www/vhosts/pron.com/httpdocs/forum/library/core/class.dispatcher.php:289] Gdn_Dispatcher->dispatchController();
[/var/www/vhosts/pron.com/httpdocs/forum/index.php:29] Gdn_Dispatcher->dispatch();

I have PHP version 7.2, mariadb 10.2, ssl.

What is this error?