How can I dispatch emails exclusively via BCC using Mailgun PHP API?

I’ve been facing an issue when sending emails solely through the BCC field with Mailgun’s PHP API. Emails send correctly when both a primary recipient and a BCC are provided, but attempts to use only a BCC address result in failure—even when an empty string is passed to the primary recipient.

function dispatchEmail($mainRecipient, $emailTitle, $emailContent, $blindList) {
    $keySecret = "";
    $hostDomain = "";
    $session = curl_init();
    curl_setopt($session, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
    curl_setopt($session, CURLOPT_USERPWD, 'api:' . $keySecret);
    curl_setopt($session, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($session, CURLOPT_CUSTOMREQUEST, 'POST');
    curl_setopt($session, CURLOPT_URL, 'https://api.mailgun.net/v3/' . $hostDomain . '/messages');
    curl_setopt($session, CURLOPT_POSTFIELDS, array(
        'from' => 'Sender Name <[email protected]>',
        'to' => $mainRecipient,
        'bcc' => $blindList,
        'subject' => $emailTitle,
        'html' => $emailContent,
        'o:tracking' => 'yes'
    ));
    $result = curl_exec($session);
    curl_close($session);
    return $result;
}

dispatchEmail($mainRecipient, $emailTitle, $emailContent, $blindList);

hey, i faced this before. try using a dummy valid address in ‘to’, mailgun seems to require a real recipient. thats been a workrund for me.