Why api stopped working on Laravel?

Question

Laravel

Sitting means learning to write api on Laravel.

Route::get('{user_id}', 'Api\[email protected]');

public function getUser($user_id) {       
    return response()->json(User::find($user_id), 200);       
}

I checked through Postman, everything is OK, I get the user and the status is 200. I turned off the computer and went to the store. Come on, I think we need to continue. Again I climb into the postman and this route does not work for me anymore. First I got a 404 error, then I reset the cache php artisan cache:clear, route:cache and now I don't get anything at all. Status 200, but no data. I have no idea where the trouble happened.