is a simple web server that can run on Windows with a couple of easy features for developers of Windows applications. This includes things like, webhooks, a modern way of accepting POST requests and responding to them. Each IIS Express site is managed on a user basis, as it’s written as a tool to assist with development.
Many web applications will attempt to communicate with one another via a specific port. And when you’re using IIS Express, you’ll need to create a socket binding to that port and allow external users to connect (again, by default, IIS Express is configured for developers to test code on their own machines). To do so, open the IIS Express config file at %userprofile%\documents\iisexpress\config\applicationhost.config (note that the userprofile is here as it’s again, per user). By default, bindings will restrict to localhost as you can see below:
<binding protocol="http" bindingInformation="*:8443:localhost" />
Copy this line and paste it below the first instance, replacing the localhost with * (make sure to leave the first line or your dev tools can’t connect to the server):
<binding protocol="http" bindingInformation="*:8443:*" />
Again, make sure to leave the first binding in place. Then restart the server and you’re good.