OneSignal REST API to send push notification, but I get a 500 error
<p>I have a Perl script I've written, and I'm trying to send a test push notification out using <strong>OneSignal</strong>. Here is my <em>JSON</em> (prettified, for readability);</p>

<pre><code> {
    "contents": {
        "en": "Here are your daily picks!"
    },
    "app_id": "id_here",
    "app_ids": ["id_here"],
    "include_player_ids": ["aabaa581-b54a-4348-81cb-00ed65c1adf8"]
 }
</code></pre>

<p>I get an error message, in plain HTML:</p>

<pre><code>  &lt;p id="message" class="text"&gt;An Unexpected Error Occurred&lt;/p&gt;
  &lt;p id="submessage" class="text"&gt;Error Code: 500&lt;/p&gt;
  &lt;p id="explanation" class="text"&gt;
    We track these errors automatically, but if the problem persists feel free to contact us.
  &lt;/p&gt;
</code></pre>

<p>Any ideas as to what am I doing wrong?</p>