title: Slack API invalid_block
body: <p>I'm building a simple slack bot and I am playing with the <code>checkboxes</code> element.</p>
  
  <p>When I return the following from my API in a JSON response to a slash-command I get an error <code>failed with the error "invalid_blocks"</code>, however, when I put this in the <a href="https://api.slack.com/tools/block-kit-builder?mode=appHome&amp;view=%7B%22blocks%22%3A%5B%7B%22elements%22%3A%5B%7B%22style%22%3A%22primary%22%2C%22text%22%3A%7B%22emoji%22%3Atrue%2C%22text%22%3A%22Create%20new%20TODO%20list%22%2C%22type%22%3A%22plain_text%22%7D%2C%22type%22%3A%22button%22%2C%22value%22%3A%22value%22%7D%2C%7B%22style%22%3A%22primary%22%2C%22text%22%3A%7B%22emoji%22%3Atrue%2C%22text%22%3A%22Help%22%2C%22type%22%3A%22plain_text%22%7D%2C%22type%22%3A%22button%22%2C%22value%22%3A%22value%22%7D%5D%2C%22type%22%3A%22actions%22%7D%2C%7B%22text%22%3A%7B%22text%22%3A%22Today%22%2C%22type%22%3A%22mrkdwn%22%7D%2C%22type%22%3A%22section%22%7D%2C%7B%22elements%22%3A%5B%7B%22initial_options%22%3A%5B%7B%22text%22%3A%7B%22text%22%3A%22Get%20Into%20the%20garden%22%2C%22type%22%3A%22mrkdwn%22%7D%2C%22value%22%3A%22foo%22%7D%5D%2C%22options%22%3A%5B%7B%22text%22%3A%7B%22text%22%3A%22Get%20Into%20the%20garden%22%2C%22type%22%3A%22mrkdwn%22%7D%2C%22value%22%3A%22foo%22%7D%5D%2C%22type%22%3A%22checkboxes%22%7D%2C%7B%22style%22%3A%22primary%22%2C%22text%22%3A%7B%22emoji%22%3Atrue%2C%22text%22%3A%22Add%20new%20Task%22%2C%22type%22%3A%22plain_text%22%7D%2C%22type%22%3A%22button%22%2C%22value%22%3A%22value%22%7D%5D%2C%22type%22%3A%22actions%22%7D%5D%2C%22type%22%3A%22home%22%7D" rel="nofollow noreferrer">block-kit-builder</a> it works perfectly (including "sending to slack" button)</p>
  
  <p>Any ideas why this is failing when I run my slash command - and is it possible to see more detailed error messages from slack?</p>
  
  <pre><code>{
    "blocks": [
      {
        "elements": [
          {
            "style": "primary",
            "text": {
              "emoji": true,
              "text": "Create new TODO list",
              "type": "plain_text"
            },
            "type": "button",
            "value": "value"
          },
          {
            "style": "primary",
            "text": {
              "emoji": true,
              "text": "Help",
              "type": "plain_text"
            },
            "type": "button",
            "value": "value"
          }
        ],
        "type": "actions"
      },
      {
        "text": {
          "text": "Today",
          "type": "mrkdwn"
        },
        "type": "section"
      },
      {
        "elements": [
          {
            "initial_options": [
              {
                "text": {
                  "text": "Get Into the garden",
                  "type": "mrkdwn"
                },
                "value": "foo"
              }
            ],
            "options": [
              {
                "text": {
                  "text": "Get Into the garden",
                  "type": "mrkdwn"
                },
                "value": "foo"
              }
            ],
            "type": "checkboxes"
          },
          {
            "style": "primary",
            "text": {
              "emoji": true,
              "text": "Add new Task",
              "type": "plain_text"
            },
            "type": "button",
            "value": "value"
          }
        ],
        "type": "actions"
      }
    ],
    "type": "home"
  }
  </code></pre>