I wrote a script integrating ID broker with WooCommerce.
After a successful purchase in the store, the broker ID authentication process should begin and the Broker ID link should be downloaded and displayed on the thank you for your purchase

page.add_action('woocommerce_before_thankyou', '');
function after_purchase_completed($order_id) {
    $order = wc_get_order($order_id);
    $process_id = 'AUT_' . $order->get_order_number() . '_' . uniqid();
    $data = array(
        'identification_channel_id' => '651d17427587d47324c683e3',
        'state' => $process_id,
    );
    
    $username = 'API Client';
    $password = 'API Key';
    $auth_token = base64_encode($username . ':' . $password);

    $response = wp_remote_post('http://i.broker.id/api/v1.0/oauth2/authorize', array(
        'headers' => array(
            'Content-Type' => 'application/json',
            'Authorization' => 'Basic ' . $auth_token
        ),
        'body' => json_encode($data)
    ));
    if (!is_wp_error($response)) {
        $response_code = wp_remote_retrieve_response_code($response);
        $response_body = wp_remote_retrieve_body($response);
        $error_message = '';
        if ($response_code !== 200) {
            $error_message = ' Error code: ' . $response_code . '. Error message: ' . $response_body;
        }
        $result = json_decode($response_body, true);
        if (isset($result['link'])) {
            echo '<p>URL: <a href="' . $result['link'] . '">' . $result['link'] . '</a></p>';
        } else {
            echo '<p>Sorry, the Broker ID authorization link could not be retrieved. Contact us for help.' . $error_message . '</p>';
        }
    } else {
        echo '<p>Sorry, there was a problem retrieving your Broker ID authorization link. Contact us for help.' . $error_message . '</p>';
    }
}

of course, I provide the correct data in place of Api Client and Api Key. I get an error:

Sorry, the Broker ID authorization link could not be retrieved. Contact us for help. Error code: 401. Error message: {„timestamp”:”2024-05-05T15:00:53.172684169+02:00[Europe/Warsaw]”,”exceptionId”:”bad.credentials”,”traceId”:”66378305d5ef962325c0e06ec7ca4c97″,”errorCode”:”66378305d5ef962325c0e06ec7ca4c97″,”message”:”Bad Authorization”}

I use Broker ID documentation:
https://i.broker.id/documentation/documentation/resources/swagger-ui/index.html#/

Can someone tell me where I’m making a mistake?