Can you provide a Debug ID from the Zotero Connector for reloading that URL?
(Note that it's almost always better to save from the article page — https://arxiv.org/abs/2406.04692 in this case — but in this case the PDF URL should work.)
Could you make sure you are running the latest version of Chrome and restart your computer? It seems like maybe there is something going wrong in Chrome itself.
Could you create a new chrome profile, install the Zotero Connector there and see if you still see the issue? Do you run any security software on your machine that you could temporarily disable?
(Note that it's almost always better to save from the article page — https://arxiv.org/abs/2406.04692 in this case — but in this case the PDF URL should work.)