Answers for ""class \"app\\http\\controllers\\api\\config\" not found","

Class 'App\Http\Controllers\File' not found

// Class 'App\Http\Controllers\File' not found
use Illuminate\Support\Facades\File;

Class 'App\Http\Controllers\File' not found

// in laravel append the following at the top of controller
use File;

Class 'App\Http\Controllers\Response' not found

use Illuminate\Support\Facades\Response;
Or
use Response;

Or use full namespace:
return \Response::json(...);

Or just use helper:
return response()->json(...);