pyrodactyl/app/Providers/SubdomainServiceProvider.php

<?php

namespace Pterodactyl\Providers;

use Illuminate\Support\ServiceProvider;
use Pterodactyl\Services\Subdomain\SubdomainManagementService;

class SubdomainServiceProvider extends ServiceProvider
{
    /**
     * Register any application services.
     */
    public function register(): void
    {
        $this->app->singleton(SubdomainManagementService::class, function ($app) {
            return new SubdomainManagementService();
        });
    }

    /**
     * Bootstrap any application services.
     */
    public function boot(): void
    {
        //
    }
}