In order to allow loading and downloading json file on your site, you have to add json extension in mime type and handler mappings in IIS windows server. By default this extension is not view-able. Therefore you will need manually mapping json extension into your IIS. To do this, you must have to get an access to your IIS, if you do not have, please request your site administrator to add this extension for you. For users host their sites on GoDaddy or other web hosting providers will need to contact their hosting provider.
Go to the IIS console and click on your site under the sites folder.
Then click the MIME Types and enter .json in the file extension and application/json in the MIME type.
Once the mime type has already been added, you can now add the json type in the mapping handlers. Go back to the site properties screen and click on Handler Mappings.
Then click the Add a script map and enter *.json in the request path and enter C:\WINDOWS\system32\inetsrv\asp.dll in the executable text box, if the asp.dll has difference location, you may want to browse the location of the file. You can add the name to Json if you want. This is used for description only.