If you click the Save to Zotero button on that page, is a PDF saved along with the metadata? Downloading PDFs from the URL/DOI for Find Available PDF relies on the same translators used from the Connector, so if those don't work via the Connector, they won't work via Find Available PDF either (unless there's an OA file with a known download URL in Unpaywall, which there isn't for this DOI).
Whether the translator could be updated to save a PDF in that case would be a separate question — my proxy doesn't have access to a PDF on that page, so I couldn't say.
Oh, well, there's no PDF URL in the embedded metadata on the main page, which is the URL your item has, so that wouldn't work. There is an embedded PDF URL for individual chapters, so those should work if you have access to them and they work via the Connector, but only for an item that actually had one of those URLs.
OK, that wasn't the DOI in your Debug ID — the book DOI was.
Adding via the chapter DOI saves for me. If that's not working for you, that's unrelated to this, but we'd need to see a Debug ID for that to say more.
And you haven't addressed what I said about whether you get a PDF for that URL with the Connector.
I'm getting the full book metadata via the chapter DOI, which is due to some weird formatting of the metadata at Cambridge, but ultimately I think still Zotero's bug.
Ah, yeah, I didn't check the saved data. Still, unrelated to Find Available PDF, which will follow the item DOI/URL and look for the PDF with the site translator.
The resource in question is:
https://www.cambridge.org/core/books/shaping-modern-shanghai/public-health-and-hygiene/B464B437CCEB3582F7DD8018633279AA
I am able to manually download the PDF from the dropdown, but I'm wondering whether that dropdown is the issue.
Whether the translator could be updated to save a PDF in that case would be a separate question — my proxy doesn't have access to a PDF on that page, so I couldn't say.
https://doi.org/10.1017/9781108303934.005
redirects to the original URL I posted
https://www.cambridge.org/core/books/shaping-modern-shanghai/public-health-and-hygiene/B464B437CCEB3582F7DD8018633279AA
Adding the item via the DOI causes Zotero to hang, and no item is added, let alone a PDF. After several minutes, I get the following error:
"Zotero could not find a record for the specified identifier. Please verify the identifier and try again."
Adding via the chapter DOI saves for me. If that's not working for you, that's unrelated to this, but we'd need to see a Debug ID for that to say more.
And you haven't addressed what I said about whether you get a PDF for that URL with the Connector.