Now, most of the websites are being developed using HTML5 and using videos on the background. It is an easy job to use the video tag.. It is advised to serve video files using a CDN, however, in case you want to host videos from your own server, you need to configure IIS to server .mp4 files. In case you don’t configure it, you will get a 404 error or an error saying “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.” Again, if you have got access to IIS , it’s a great thing but what if you’re hosting the website on a shared server where you don’t have access to IIS Server? In this post, we will see how can we enable IIS Server to serve .mp4 files through web.config file.