Can't upload paper which matches deleted entry

I tried adding an item via the paperpile extension in Chrome but it didn’t add any metadata, so I deleted the option and tried adding by directly uploading the PDF. However, after uploading it gives me an error message saying nothing was uploaded because it was “identical to [untitled item] - [No title].pdf” Not sure how to fix this?

That can only happen if you already have exactly the same PDF in your library. To avoid duplicates we don’t allow users to upload PDFs with exactly the same content multiple times.

It seems the PDF when you originally added it was not recognized, that’s why it’s called “untitled item”. Can you check your “untitled items”, it should contain the same PDF you are trying to upload.

I understand that. The problem is that this untitled item was deleted, but it still won’t let me upload! (I finally fixed the problem by adding the entry another way and then attaching the PDF to that new entry.)

Are you sure you have no other copy of it in your library?

How did you delete it? Trashed or deleted completely? (It should not really matter because that should not happen even if you have just trashed the item)

No other copy. When you get the error message it offers a link to the duplicate item, but that link did not work…