Why does the invalid cookie domain (Session info: headless chrome=87.0.4280.88) error occur?

Question

Parsing

$client = \Symfony\Component\Panther\Client::createChromeClient(null, [
        '--window-size=1366,768',
        '--headless',
        '--disable-gpu',
    ],['port' => 9115]);

    foreach ($cookie_arr as $key=>$value) {
        $cookie = new Cookie($key, $value, null, '/', 'site.org');
        $client->getCookieJar()->set($cookie);
    }

    $crawler = $client->request('GET', 'https://site.org/page');

My cookies are stored in the $cookie_arr array.
I am using Symfony/Panther. The fifth parameter to the Cookie class is domain.