I'm trying to send an email with PHP 7.1 via cURL. I receive the email but it doesn't have the subject, body (it's empty) and in "to" field I get "undisclosed recipients". Am I missing any parameters inside curl_setopt_array?
$postData = ["from" => John Doe,
             "body" => "this is a test",
             "to" => "xxxxxxxx@yyyyy.zzz",
             "subject" => A simple test,
];
$ch = curl_init();
curl_setopt_array($ch, [
     CURLOPT_URL => 'smtp.mydomain.com:25/mydomain.com',
     CURLOPT_MAIL_FROM => '<no-reply@mydomain.com>',
     CURLOPT_MAIL_RCPT => ['xxxxxxxx@yyyyy.zzz'],
     CURLOPT_HTTPHEADER => array(
         "Accept: application/json",
         "Content-Type: application/json"
      ),
     curl_setopt($ch, CURLOPT_POST, true),
     CURLOPT_POSTFIELDS => json_encode($postData),
     CURLOPT_UPLOAD => true,
]);
curl_exec($ch);
curl_close($ch);