Respond.js (IE8, Bootstrap 3) works on localhost, but not in production

Question

I've browsed through all other IE8/Respond.js questions here on SO, but no luck so far.

When I test on localhost in IE8 emulator, I get the same error as in production, but Respond works despite that. First we see a broken page for a second, then Bootstrap's grid comes in place and everything is okay. However, in production it stays broken.

The error I get comes from respond-proxy.html file, line 46 (ajax): Permission denied

This is what I got in my base html file:

<!-- HTML5 Shim and Respond.js IE8 support of HTML5 elements and media queries -->
<!-- WARNING: Respond.js doesn't work if you view the page via file:// -->
<!--[if lt IE 9]>
    <script src="https://oss.maxcdn.com/html5shiv/3.7.2/html5shiv.min.js"></script>
    <script src="https://oss.maxcdn.com/respond/1.4.2/respond.min.js"></script>

{# <!-- Respond.js proxy on external server -->#}
<link href="https://maxcdn.bootstrapcdn.com/respond-proxy.html" id="respond-proxy" rel="respond-proxy" />

{# <!-- Respond.js redirect location on local server -->#}
    <link href="{% static "img/respond.proxy.gif" %}" id="respond-redirect" rel="respond-redirect" />

{# <!-- Respond.js proxy script on local server -->#}
    <script src="{% static "js/respond.proxy.js" %}"></script>

<![endif]-->

I've tried moving it around (end of head, end of body etc.) but nothing seems to work in production. We host our static files on S3 (CloudFront). We copied CORS config from here: https://github.com/scottjehl/Respond/issues/152

I also tried copying the respond-proxy.html into a file hosted along with our static files, but still get the same "Permission denied" error.

Any solutions, workarounds, hints and suggestions are more than welcome.

Edit: I also tried some substitutes like css3-mediaqueries-js, but that didn't work at all.