Facebook Messenger Bot verification
<p>I submitted my facebook messenger bot for app review and the rejection reason was "<em>received no response</em>". </p>

<p>I've tested my bot from my own account and some other testers that I added to my facebook app for testing.
However, when I try to test using the default <code>Open Graph Test User</code> I don't get any response. The Send Message API fails with error:</p>

<pre><code>{"error": {"message":"(#100) No matching user found", "type":"OAuthException", ...}}
</code></pre>

<p>What am I doing wrong here? How can I send message to test users using the Send/Receive message API?</p>