Try to many time ,has error like file.
Please login to try.
& install page builder => new page
error like~
Fatal error: require_once(): Failed opening required '/hd2/.XDATA/home/transtep/www/msc-ja-web/administrator/components/com_menus/models/item.php' (include_path='.:/ram/php7.3/lib/php') in /hd2/.XDATA/home/transtep/www/msc-ja-web/administrator/components/com_jabuilder/models/page.php on line 15
& I try T4 : error like this
Warning: Declaration of T4pagebuilderModelPage::preprocessForm(JForm $form, $data, $group = 'page') should be compatible with Joomla\CMS\MVC\Model\FormModel::preprocessForm(Joomla\CMS\Form\Form $form, $data, $group = 'content') in /hd2/.XDATA/home/transtep/www/msc-ja-web/administrator/components/com_t4pagebuilder/models/page.php on line 551