OpenStreetMap does not work on Wordpress.com

We've had a series of reports from people who use Wordpress.com that their map is filled with 403 blocked tiles.

Wordpress.com does not allow iframe tags in the Custom HTML block; instead, storymaps must be embedded using the embed block, which constructs an iframe with the storymap URL. The constructed iframe has sandbox="allow-scripts" which prevents the referrer from being sent with the tile request, which is against OpenStreetMap's policy.

We cannot change the way that Wordpress handles embeds. For now, the workaround is to use a different basemap. The only no-cost basemap directly supported by StoryMapJS is "Cooper-Hewitt: Watercolor".

Users could also consider using Mapbox Studio or Stadia Maps, each of which have some no-cost options. Mapbox Studio's pay-as-you-go plan might never get to the point of costing money; Stadia's no-cost option is only available for non-commercial use. Of course, if you have access to some other "slippy map" URL, you could use that with the "custom" map type.

To consider: should StoryMapJS be updated to recognize when self.origin === "null" and the basemap is set to OpenStreetMap and

• switch to another map
• message the viewer (who may not be the author)
• both
• neither

Start by reproducing a StoryMapJS with the OpenStreetMap basemap inside a WordPress.com embed block, where the sandboxed iframe produces 403 tile requests. Decide whether StoryMapJS should detect a null origin, switch basemaps, notify viewers, or do nothing; done requires an agreed behavior and verification that the embedded map no longer fails or clearly informs users.