If you can't open or buy an article, the publisher most likely didn't deliver its digital version to us. This can be because of technical issues or because something just went wrong or was forgotten.
What could also be the issue, is that the article was written by a freelance journalist whose contract doesn't include sales via Blendle. We're currently working on fixing this with publishers.
Buying a complete edition doesn't guarantee that all articles in it are available for reading, and we'd recommend browsing through the publication first to see if the articles you want to read are actually readable. You can check for this by hovering your mouse pointer over the article so a preview pops up and the article gets a grey overlay.