One of those things that's really simple but took me an hour to find: If you want to redirect a request in nginx when a page is not found to an external site,
including the path and whatever other things are in the uri, it's just:
error_page 404 https://other-site.com/$request_uri;It was right there in the
official nginx docs, but I unconsciously look elsewhere first because of previous experiences finding them really abstruse.