Elif,
Yes, loading some maps can be slow on mobile phones because of slow connections and slower processors that mobile devices have. If the mobile experience is very important to your audience you can follow the advice in this blog to host the story map yourself and provide an alternate, mobile-friendly version of your story.
You can also limit the amount of dynamic content in your story and link out to maps or other content so readers on a desktop who are able to view it can open that content in a separate browser tab, but mobile users still get a good experience.
In the future, we want to add the ability in our Story Map builders for authors specify alternate media that will load on slower connections/mobile phones. So, for example, you could upload an image that would load on mobile devices instead of a 3D scene or an embedded app.
Owen
Owen Evans
Lead Product Engineer | StoryMaps
