OK. I can reach the services directory for the web server providing maps for the Hillsboro Maps application from my office over port 6080, but not 6443 - and not over 80 or 443 either. I think that's the issue, since story maps require HTTPS these days. My guess is that you have port forwarding configured at the router level to forward traffic internally on port 6080, but not 6443. Personally, I'd keep the GIS Server internal, install the web adaptor on the DMZ machine, and allow the web adaptor machines IP access to the GIS Server on ports 6080/6443.
An Important Message About Web Security and Story Maps