2111543382，zotero couldn't save pdfs from pubmed, I tried to update the connector but failed, also the PC zotero updates its translator but didn't work.
You should install the current version of the Zotero Connector from the download page.
Beyond that, we'd want an example URL and a Debug ID (different from a Report ID) from Zotero (instead of the Zotero Connector) for a save attempt that failed to download a PDF.
If you mean Pubmed, not Pubmed Central, though, there aren't any PDFs on the platform, so Zotero working normally would just save the item metadata, not any PDFs. You should get PDFs on Pubmed Central, so if that's not the case, see above.
Zotero does save PDFs when saving from the Pubmed page much of the time (most of the time in my experience), but that's not from Pubmed, which has no pdfs, as adamsmith mentioned. Zotero is just working behind the scenes and finding the pdf for you likely from the journal's webpage.
Depending on the network you are on (university, VPN or home), you may have different luck in getting a pdf. The Pubmed translator may, otherwise, download the Pubmed Central pdf, which is probably an accepted or submitted version.
In cases where you don't get a pdf with the item saved from Pubmed, you may have to download and manually attach the pdf yourself. Or you could simply save the item from the journal's webpage - that may get you the pdf.
Upgrade Storage
Beyond that, we'd want an example URL and a Debug ID (different from a Report ID) from Zotero (instead of the Zotero Connector) for a save attempt that failed to download a PDF.
Depending on the network you are on (university, VPN or home), you may have different luck in getting a pdf. The Pubmed translator may, otherwise, download the Pubmed Central pdf, which is probably an accepted or submitted version.
In cases where you don't get a pdf with the item saved from Pubmed, you may have to download and manually attach the pdf yourself. Or you could simply save the item from the journal's webpage - that may get you the pdf.