I’ve written up a wiki at my company. I want to make it public at some point. But here’s my note on a 403:
It shouldn’t be anything to worry about, it just means the contents of your server are currently ‘hidden’, but probably updated. Examining the contents of your server, (typically C:\inetpub\wwwroot\UGSAPI), for a “database.sqlite” file should indicate successful deployment. This file will only show up if someone marked a build as good/bad or left a comment on a build through UGS.
As for the 404, that’s not a valid URL I don’t think. Here’s an example of how I tested the server through my browser: http://server/UGSAPI/api/cis?GET
Our server is internal so I didn’t need a domain, just the address on our local net. I named the web app UGSAPI. /cis?GET may no longer be valid since they changed the API, but you can try it. It might be /latest?GET since a newer version of UE4. Should return an XML page for you.