Web gateway add username and password authentication on a standalone on the web server

Hi Community,

We have web gateway installed  as a standalone on the web server and when I access it through the direct link https://mydomain.com/csp/bin/Systems/Module.cxw, it doesn't require authentication it just opens as per screenshot below.

There is a requirement to add authenticate using username and password as with the webgateway installed with iris, I want to get to the below screen before gaining access to web gateway.

Thanks in advance.