Fatal error: Uncaught Error: Class 'Illuminate\Notifications\Messages\SimpleMessage' not found in /mnt/volume_lon1_01/backend/admin/vendor/laravel/framework/src/Illuminate/Notifications/Messages/MailMessage.php:11 Stack trace: #0 {main} thrown in /mnt/volume_lon1_01/backend/admin/vendor/laravel/framework/src/Illuminate/Notifications/Messages/MailMessage.php on line 11