Problem with the script and the database

[MinerPL]

Hello I am writing with a problem related to creating a custom hook. I have already written all the ready code but unfortunately not everything works in it as it should. Below I send the code and the error. In the screenshot I send what logModuleCall returns.
Code:

<?php

 

use WHMCS\Database\Capsule;

 

add_hook('AfterShoppingCartCheckout', 1, function($vars) {

    $orders = Capsule::table('tblorders')

        ->where('id', $vars['OrderID'])

        ->get()

        ->first();

 

    logModuleCall('BetterAffilance', 'Sended data', json_encode($orders), json_encode($vars));

 

    $partners = [

        'minerpl' => 2,

    ];

 

    if($partners[$orders->promocode]) {

        logModuleCall('BetterAffilance', 'User use partner code!', $partners[$orders->promocode], $vars['ServiceIDs'][0]);

        try {

            Capsule::connection()->transaction(

                function ($connectionManager)

                {

                    /** @var \Illuminate\Database\Connection $connectionManager */

                    $connectionManager->table('tblaffiliatesaccounts')->insert(

                        [

                            'affiliateid' => $partners[$orders->promocode],

                            'relid' => $vars['ServiceIDs'][0],

                        ]

                    );

                }

            );

        } catch (\Exception $e) {

            logModuleCall('BetterAffilance', 'Error when inserting data to database', $e->getMessage(), $e->getMessage());

        }

    }

});

Error:

SQLSTATE[23000]: Integrity constraint violation: 1048 Column 'affiliateid' cannot be null (SQL: insert into `tblaffiliatesaccounts` (`affiliateid`, `relid`) values (?, ?))