I've got a 10.9.1 ArcGIS Enterprise site up and running and am trying to access the Portal web Adaptor config page. I've logged into the Web Adaptor (Adapter?) server, clicked the start menu link to the Portal Web Adaptor page and I get a "not found" result. If I go to the URL which reads "https://localhost/arcgisportal/webadaptor" and change it to "http://... ... ..." I get the standard entry page for the web adaptor config. The one where you pick if you want to do an ArcGIS Server or Portal web adaptor. I pick the Portal option and again, the resulting page is a "Not Found" web page. Again, I go to the URL and do http instead of https and I get an ArcGIS Web Adaptor page with the following message, "Portal for ArcGIS configuration requires HTTPS enabled on the web server. Please use an HTTPS url to access this page."
Ok, so on the surface, I understand what's going on here but from a practical perspective, I'm baffled. What's the trick to get to the config page? I don't have https configured for the internal machine name, only for the external DNS name. This was true when I initially installed the Portal Web Adaptor so I'm stumped as to why this is an issue now. What's the magic sauce to get into the Portal Web Adaptor config page?