MathJax Test Page Warning

I download the latest MathJax package, and deploy it in my own website(IIS).

I include the js file in index.html file as below:

<script type="text/javascript" src="http://localhost/mysite/MathJax/MathJax.js"></script>

But things are wired that there's warning like below:

I change the code, use the online js, like below:

<script type="text/javascript" src="http://ift.tt/1bX3mfK"></script>

Everything seems ok.

What confuse me is that I just only change the include file. I notice that there's a hint when I load the page

Web-Fonts not available -- using image fonts instead

But I don't know why. So does anyone can tell me what happened?