https://community.esri.com/t5/arcgis-online-questions/web-maps-not-displaying-in-storymaps/m-p/11863...
The above link is actually reporting issues, however @OwenGeo suggested that we post here, too. Rather than post a lengthy repeat, please follow the link if you are having issues with your hosted features showing up in maps embedded in StoryMaps, the new version of the Map Viewer - or other issues related to these topics.
That's what the post in the other thread (link) is about.
