https://www.isbn-international.org/content/what-isbn

All of them... Even them that I have used before. Can I somewhere post a screenshot?

D519615217

We'll respond in English, but you can post in Danish — that's no problem.

That Debug ID shows a book being successfully saved, and then 15 seconds later an auto-sync occurs and the new item is uploaded, but then 30 seconds later you seem to be getting the "Zotero kunne ikke finde nogen identifikatorer i dit input." error. That's very strange.

What exactly are you experiencing on your end? I assume you see it add the item after you press Return? What happens between when you press Return and when the alert pops up?

But did you get an error just now? Because from your Debug ID it looks like 1) the item is saving and 2) you're getting an error, which shouldn't be possible — it should be one or the other. So there may still be some sort of problem.

For what it's worth, I'm actually getting inconsistent results right now from Open WorldCat, which is one of the sources we use to look up ISBNs. It's possible there's a temporary problem with their service. That shouldn't explain getting an error after a successful save, though.

Can you just post the two ISBNs you're trying here?

Please just post an ISBN that's failing here, not a Debug ID.

No, please stop posting Debug IDs. We need the actual ISBN that's failing for you.

Right, that's not a valid ISBN.

The reason we couldn't see anything in the Debug ID is because it's not a valid ISBN, so Zotero doesn't even detect it as a valid identifier to try. The other valid ISBN you entered is getting saved properly. So everything is working normally.

That one isn't registered in any of the ISBN databases Zotero uses. If something is only published by a Danish publisher, that's entirely possible.

"That one isn't registered in any of the ISBN databases Zotero uses. If something is only published by a Danish publisher, that's entirely possible."

Plejer bare ikke være et problem...

Okay, der må være en fejl i det nummer, jeg har fået af min medstuderende. Bare det virker, så er det jo fint, og det lader
det til, at det gør nu! tusind tak for hjælpen, kan du have en dejlig dag!