How can I solve the Laravel Shopify plugin api method error?

Hello Everyone,

I’ve installed the plugin osiset / laravel-shopify and I followed the instructions for installation.

Now, I received the following error when I call the api method:

Error
Call to undefined method stdClass::api()

My user model:

use Osiset\ShopifyApp\Contracts\ShopModel as IShopModel;
use Osiset\ShopifyApp\Traits\ShopModel;

class User extends Authenticatable implements IShopModel
{
use Notifiable, ShopModel;
...

My controller:

public function themeUpdate(ShopvoteShops $shopvoteShop, $request = null)
{
$user = DB::table('users')->first();
$shopvoteShop = ShopvoteShops::where('url', $user->name)->first();
$shop = Auth::user();

$response = $user->api()->rest('GET', '/admin/script_tags.json');

Basically, the instances User and Auth everytime are empty and I can’t call for example $shop->api(), because

Error
Call to a member function api() on null.

I will be glad to hear how to fix this issue.

Thank you!