I finally got through all the hoops to create an offline map area. Having our Portal admin look at the error logs to see more than just "Failed" was helpful and led to this https://support.esri.com/en-us/knowledge-base/error-failed-to-create-replica-multiple-layers-are-refe-000027576 -- I had more than one layer pointing a source. Why can't I do that?). Anyway, I created an area using the web interface, but now when I go into the app, I don't see the already created area. It's only after I choose Add Offline Area and then Download Area do I see the already created area. So I hit Stop Download on the new area, and then I can download the already created area. But if I don't do that, and then go back to Maps, there is again no option to download the already created area. I again have to create one on the mobile app, which defeats the purpose of "precreating" an area. Why is this interface so confusing? Why can't I just precreate an area for our users to see and download directly, without having to jump through these hoops?