Wechat sandbox unable to configure setting url and token
<p>I am trying to setup Wechat's sandbox account and I am following <a href="http://blog.reigndesign.com/blog/building-a-wechat-weixin-robot/" rel="nofollow noreferrer">this site</a>. </p>

<p>I am pointing the URL to my site and I've tried different settings for the Token. However, I am unable to press submit because I see this weird "Unable to configure" error without any explanation whatsoever. </p>

<p>Any ideas? </p>

<p><a href="https://i.stack.imgur.com/aZbJN.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/aZbJN.png" alt="enter image description here"></a></p>