title: YouTube Subscriptions: insert fails with error 400
body: <p>I want to subscribe for a specific channel, to achieve this I use their <a href="https://developers.google.com/youtube/v3/docs/subscriptions/insert#usage" rel="nofollow noreferrer">official docs</a>. There is a <strong>Execute button</strong> right on top page:
  <a href="https://i.stack.imgur.com/1kSsz.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1kSsz.jpg" alt="enter image description here"></a></p>
  
  <p>That supposed to demonstrate the request, after I grant access it throws an error:</p>
  
  <pre><code>    /**
   * API response
   */
  {
    "error": {
      "errors": [
        {
          "domain": "youtube.subscription",
          "reason": "publisherRequired",
          "message": "The subscription resource specified in the request must use the snippet.resourceId property to identify the channel that is being subscribed to."
        }
      ],
      "code": 400,
      "message": "The subscription resource specified in the request must use the snippet.resourceId property to identify the channel that is being subscribed to."
    }
  }
  </code></pre>
  
  <p>But the request body contains <code>snippet.resourceId</code> :</p>
  
  <pre><code>{"0":{"name":"snippet.resourceId.kind","value":"youtube#channel"},"1":{"name":"snippet.resourceId.channelId","value":"UC_x5XG1OV2P6uZZ5FSM9Ttw"}}
  </code></pre>