That's really strange. I've implemented this a few times, referring back to this episode, and didn't have any issues with it's implementation. I did use the Cloudflare Proxy on those apps, so I wonder if that sets something in the header that could make a difference. It's pretty annoying to test those kinds of things out since the browser does some level of caching. It's usually a dance of having to clear my local DNS settings and the browser's.