Handler does not exist

ao tentar rodar a aplicação com php -S localhost:8000 -t public/ da um erro

Fatal error: Uncaught ReflectionException: Class Illuminate\Foundation\Exceptions\Handler does not exist in C:\xampp\htdocs\CodeAgenda\vendor\illuminate\container\Container.php:749 Stack trace: #0 C:\xampp\htdocs\CodeAgenda\vendor\illuminate\container\Container.php(749): ReflectionClass->__construct('Illuminate\Foun...') #1 C:\xampp\htdocs\CodeAgenda\vendor\illuminate\container\Container.php(644): Illuminate\Container\Container->build('Illuminate\Foun...', Array) #2 C:\xampp\htdocs\CodeAgenda\vendor\laravel\lumen-framework\src\Application.php(211): Illuminate\Container\Container->make('Illuminate\Foun...', Array) #3 C:\xampp\htdocs\CodeAgenda\vendor\illuminate\container\Container.php(231): Laravel\Lumen\Application->make('Illuminate\Foun...', Array) #4 C:\xampp\htdocs\CodeAgenda\vendor\illuminate\container\Container.php(746): Illuminate\Container\Container->Illuminate\Container{closure}(Object(Laravel\Lumen\Application), Array) #5 C:\xampp\htdocs\CodeAgenda\vendor\illuminate\container\Container.php(644): Illuminate\C in C:\xampp\htdocs\CodeAgenda\vendor\illuminate\container\Container.php on line 749