Cannot resolve argument $slackOauthService of "AppControllerPanelSlackSigninController::afterOauth()": Cannot autowire service "AppServiceSlackSlackOauthService": argument "$httpClient" of method "__construct()" references interface "GuzzleHttpClientInterface" but no such service exists. Did you create a class that implements this interface?

public function __construct( ClientInterface $httpClient, EntityManagerInterface $em ) {
        $this->httpClient = $httpClient;
        $this->em         = $em;
    }

services:
# default configuration for services in *this* file
_defaults:
    autowire: true      # Automatically injects dependencies in your services.
    autoconfigure: true # Automatically registers your services as commands, event subscribers, etc.

# makes classes in src/ available to be used as services
# this creates a service per class whose id is the fully-qualified class name
App:
    resource: '../src/*'
    exclude: '../src/{DependencyInjection,Entity,Migrations,Tests,Kernel.php}'

# controllers are imported separately to make sure services can be injected
# as action arguments even if you don't extend any base controller class
AppController:
    resource: '../src/Controller'
    tags: ['controller.service_arguments']