Unknown error (invalid_array_arg)

[viperdigo]

I'm trying use attachment, however, I can't.

I'm using this:

 public function indexAction()
    {

        $payload = new ChatPostMessagePayload();
        $payload->setChannel('#saopaulo-dev-qa');   // Channel names must begin with a hash-sign '#'
        $attachment = new Attachment();
        $attachment->setText('Test Text');
        $attachment->setColor('good');
        $attachment->setTitle('Teste Title');

        $attachmentField = new AttachmentField();
        $attachmentField->setTitle('Test Title Field');
        $attachmentField->setValue('Test Value Field');
        $attachment->addField($attachmentField);
        $payload->addAttachment($attachment);

        $response = $this->get('cl_slack.api_client')->send($payload,'xoxb-194306641143-i99KHJANwLCZTS84qpFR4G7z');


        if ($response->isOk()) {
            // do what you want...
        } else {
            echo sprintf('Something seemed to have gone wrong: %s', $response->getErrorExplanation());
        }

    }

and the response is that: Something seemed to have gone wrong: Unknown error (invalid_array_arg)

I not found in the documentation how to use an attachment, maybe I use badly. Anybody help me, please?