Fatal error: Uncaught Error: Class "WP_Upgrader_Skin" not found in /home/ammer/public_html/wp-admin/includes/class-plugin-upgrader-skin.php:18 Stack trace: #0 /home/ammer/public_html/wp-admin/includes/class-wp-upgrader.php(16): require_once() #1 /home/ammer/public_html/wp-content/plugins/themegrill-demo-importer/src/Importers/PluginImporter.php(18): require_once('/home/ammer/pub...') #2 /home/ammer/public_html/wp-content/plugins/themegrill-demo-importer/src/Importers/PluginImporter.php(14): ThemeGrill\Demo\Importer\Importers\PluginImporter->includes() #3 /home/ammer/public_html/wp-content/plugins/themegrill-demo-importer/src/Services/ImportService.php(26): ThemeGrill\Demo\Importer\Importers\PluginImporter->__construct() #4 /home/ammer/public_html/wp-content/plugins/themegrill-demo-importer/src/Controllers/ImportController.php(17): ThemeGrill\Demo\Importer\Services\ImportService->__construct() #5 /home/ammer/public_html/wp-content/plugins/themegrill-demo-importer/src/RestApi.php(22): ThemeGrill\Demo\Importer\Controllers\ImportController->__construct() #6 /home/ammer/public_html/wp-content/plugins/themegrill-demo-importer/src/Traits/Singleton.php(27): ThemeGrill\Demo\Importer\RestApi->init() #7 /home/ammer/public_html/wp-content/plugins/themegrill-demo-importer/src/Traits/Singleton.php(18): ThemeGrill\Demo\Importer\RestApi->__construct() #8 /home/ammer/public_html/wp-content/plugins/themegrill-demo-importer/src/App.php(39): ThemeGrill\Demo\Importer\RestApi::instance() #9 /home/ammer/public_html/wp-content/plugins/themegrill-demo-importer/src/App.php(21): ThemeGrill\Demo\Importer\App->init_hooks() #10 /home/ammer/public_html/wp-content/plugins/themegrill-demo-importer/src/Traits/Singleton.php(27): ThemeGrill\Demo\Importer\App->init() #11 /home/ammer/public_html/wp-content/plugins/themegrill-demo-importer/src/Traits/Singleton.php(18): ThemeGrill\Demo\Importer\App->__construct() #12 /home/ammer/public_html/wp-content/plugins/themegrill-demo-importer/themegrill-demo-importer.php(57): ThemeGrill\Demo\Importer\App::instance() #13 /home/ammer/public_html/wp-settings.php(589): include_once('/home/ammer/pub...') #14 /home/ammer/public_html/wp-config.php(113): require_once('/home/ammer/pub...') #15 /home/ammer/public_html/wp-load.php(50): require_once('/home/ammer/pub...') #16 /home/ammer/public_html/wp-blog-header.php(13): require_once('/home/ammer/pub...') #17 /home/ammer/public_html/index.php(17): require('/home/ammer/pub...') #18 {main} thrown in /home/ammer/public_html/wp-admin/includes/class-plugin-upgrader-skin.php on line 18