It works fine in Firefox 11 but not in IE and Chrome. By default, IIS6 does not serve .json (no wildcard
MIME type). So you will see a 404 not found thrown.
By default, IIS in Windows Server 2003 and beyond does not serve files that aren’t of a MIME type that it knows about (instead returning 404 errors).
So, to serve up JSON files you need to add a MIME type to IIS to allow it to serve that type of file. You can set it at the site level or at the server level.
When using custom fonts on Windows Azure, users have reported issues. For example, Font Awesome icons would not display. Or even if the fonts do display, it might not display correctly on some devices, such as Windows Phones.
In other cases, you may have a file type that does not map to the right MIME type.
In fact, I exposed most of the JSON files with the .txt extension just to avoid the issue of IIS not serving up .JSON files as expected.
It turns out — the issue is that IIS 7 – 8.1 serves up the wrong MIME type for web font files. So you need to be sure the right MIME types are being served up for your font files, as shown here: Proper MIME type for fonts.
When deploying to an IIS servers you need to add MIME support.