Api get方法在Laravel 5.7中返回404

API route URI registered using the GET method and the callback function from a particular Controller and it returns a 404 view

API route was grouped inside a prefix and tried to manually attach the API onto the URI, but when I use a post method it works just fine.

Route.php

Route::group(['prefix' => '/api'], function() {
    Route::get('/avatar/{avatar}', 'AvatarController@avatar');
});

AvatarController.php

public function avatar($avatar) {
    $path = storage_path('app/avatars/' . $avatar);

    if (!File::exists($path)) {
        abort(404);
    }

    $file = File::get($path);
    $type = File::mimeType($path);

    $response = Response::make($file, 200);
    $response->header("Content-Type", $type);

    return $response;
}

Image file