How to fix Array to string conversion error in Ortober CMS?

Question

Laravel

I recently started working with Ortober CMS, and I encountered an Array to string conversion error when creating an entry in the admin section.
There are two models Order and Service
Order - orders
Service - services
Many-to-many relationships through an intermediate table.
In Order, I display a list of services through a dropdown list.
In the administrative section of the site in the form for creating a new order, you must select one of the services in the list via dropdown.
snapshot 1:
snapshot 2:
I've retrieved the list of services using the getServicesOptions method.

namespace Alex\Services\Models;

use Model;
use Alex\Services\Models\Service;
/**
 * Model
 */
class Order extends Model
{
    use \October\Rain\Database\Traits\Validation;
    
    /*
     * Disable timestamps by default.
     * Remove this line if timestamps are defined in the database table.
     */
    public $timestamps = false;


    /**
     * @var string The database table used by the model.
     */
    public $table = 'alex_services_orders';

    /**
     * @var array Validation rules
     */
    public $rules = [
    ];

     /*Relations*/

     public $belongsToMany = [
        'services' =>[
            'Alex\Services\Models\Service',
            'table' => 'alex_services_services_orders',
            'order' => 'name'
        ]

    ];

    public function getServicesOptions(){
        return Service::lists('name', 'id');
    }
}

But when saving record I get error Array to string conversion
snapshot 3