Somehow you will get a 403 error message on your browser, because the extension of file that we want to open is unregistered on the server.

HTTP Error 404.3 ?€“ Not Found
The 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.

For the example, the extension file is .avs so you can add mime type .avs to make it work on your browser, by following these steps:
- Login to Plesk
- Click your website
- Click Web Server Settings
- On MIME types field, you can add the mime type there (but you need to find the combination of the mime type first i.e: *.avs the combination is video/avs-video)
- Click OK