GetUserFromToken does not exist

routes.php
$api->version('v1', function ($api) {

$api->group(['namespace'=>'App\Api\Controller'],function ($api){
    $api->post('user/login','AuthController@authenticate');
    $api->group(['middleware'=>'jwt.auth'],function ($api){
        $api->get('lessons','LessonsController@index');
    });
});

});
Kernel.php
protected $routeMiddleware = [

    'auth.basic' => \Illuminate\Auth\Middleware\AuthenticateWithBasicAuth::class,
    'jwt.auth' => Tymon\JWTAuth\Middleware\GetUserFromToken::class,
    'jwt.refresh' => Tymon\JWTAuth\Middleware\RefreshToken::class,

];

当我访问lessons路由时报{"message":"Class App\\Http\\Tymon\\JWTAuth\\Middleware\\GetUserFromToken does not exist","code":-1,"status_code":500}，这是什么原因。