Its a CORS issue. It happen when the API doesn’t allow cross domain origin. The browser will block the request. We made an option specially to overcome this limitation. You can select Make this reques through a server and it will works!
Static are fetched on the backend! Static are never fetched from the browser.
In the editor you can fetch them multiple time, but on the published app a static collection is fetched only at the build time, we store them and serve them when needed, this is how you can use them to build static collection page, because we fetch them at the build time and create a page for every item in the static collection.