reply-to mailjet v3 not working

[sumeetsadarangani]

reply to not working....
it does not show reply-to address.

$params = array(
        "method" => "POST",
        "from" => $from_email,
        "to" => $to_email,
        "subject" => $subject,
        "html" => $message_body,
        "Headers" => [
                       "Reply-To" => $reply_to_email
                      ]
);

I also tried:

$params = array(
        "method" => "POST",
        "from" => $from_email,
        "to" => $to_email,
        "subject" => $subject,
        "html" => $message_body,
        "Reply-To" => $reply_to_email
 );

email is sent but not with reply-to option