403 Forbidden: Are.na thumbnails

I've run into an issue when sharing IMDb links to my public Are.na watchlist board (linked here). For years, pasting an IMDb URL into Are.na automatically generated a webpage preview image. However, now every IMDb link I add displays a white page with "403 Forbidden." The link itself still works to take you to the correct IMDb page -- the issue is the preview thumbnail.

I've tried copying both the page URL and IMDb's share link, but neither works.

Has IMDb changed something that prevents external sites from generating link previews? Is there any way to restore the thumbnail previews?

Any support would be greatly appreciated. Thank you!