While working with a json file today I got the following error from server:
HTTP Error 404.3 - Not FoundThe page you are requesting cannot be served because of the extension configuration. If the page is a script, add a handler. If the file should be downloaded, add a MIME map.
The solution was to add the mime type in the web,.config like this:
<mimeMap fileExtension=".json" mimeType="application/json" />