How to get page names in permalinks with a Windows server

I’m on a Windows server for my site (privacyhorizon.com) and having a couple issues. One major one is that only the “Default” permalink structure will show my pages. When I change it to anything else, like post name, I get a 404 when I try to go to those pages. How can I use postname so that I can get permalinks like privacyhorizon.com/about, with a Windows server?