Mandrill_HttpError – 对消息/发送模板的API调用失败：SSL证书问题：无法获取本地颁发者证书

我不清楚Mandrill如何连接到我的本地发行人证书.我的Web服务器确实有一个有效的证书,可以成功显示HTTPS页面.

有任何想法吗？

$mandrill = new Mandrill('MyMandrillAPIKey');

        $message = array(
            'subject' => 'Test message','from_email' => 'MyEmailAddress','html' => '<p>this is a test message with Mandrill\'s PHP wrapper!.</p>','to' => array(array('email' => 'MyEmailAddress','name' => 'David Splat')),'merge_vars' => array(array(
                'rcpt' => 'MyEmailAddress','vars' =>
                array(
                    array(
                        'name' => 'FIRSTNAME','content' => $fName),array(
                        'name' => 'LASTNAME','content' => $lName)
            ))));

        $template_name = 'MyTemplateName';

        $template_content = array(
            array(
                'name' => 'main','content' => 'Hi *|FIRSTNAME|* *|LASTNAME|*,thanks for signing up.'),array(
                'name' => 'footer','content' => 'Copyright 2014.')

        );

        print_r($mandrill->messages->sendTemplate($template_name,$template_content,$message));

    } catch(Mandrill_Error $e) {
        // Mandrill errors are thrown as exceptions
        echo 'A mandrill error occurred: ' . get_class($e) . ' - ' . $e->getMessage();
        throw $e;
    }