app/bundles/EmailBundle/Stats/Helper/FailedHelper.php

<?php

namespace Mautic\EmailBundle\Stats\Helper;

use Mautic\EmailBundle\Stats\FetchOptions\EmailStatOptions;
use Mautic\StatsBundle\Aggregate\Collection\StatCollection;

class FailedHelper extends AbstractHelper
{
    public const NAME = 'email-failed';

    public function getName(): string
    {
        return self::NAME;
    }

    /**
     * @throws \Exception
     */
    public function generateStats(\DateTime $fromDateTime, \DateTime $toDateTime, EmailStatOptions $options, StatCollection $statCollection): void
    {
        $query = $this->getQuery($fromDateTime, $toDateTime);
        $q     = $query->prepareTimeDataQuery('email_stats', 'date_sent', $options->getFilters());

        $this->limitQueryToEmailIds($q, $options->getEmailIds(), 'email_id', 't');

        if (!$options->canViewOthers()) {
            $this->limitQueryToCreator($q);
        }

        $q->andWhere($q->expr()->eq('t.is_failed', ':true'))
            ->setParameter('true', true, 'boolean');

        $this->addCompanyFilter($q, $options->getCompanyId());
        $this->addCampaignFilter($q, $options->getCampaignId());
        $this->addSegmentFilter($q, $options->getSegmentId());

        $this->fetchAndBindToCollection($q, $statCollection);
    }
}