404 Not Found Error Through a Proxy

What the error means

The 404 code means the server did not find a resource at the requested URL. The HTTP standard (RFC 9110) adds an important detail: a server may answer 404 even when the resource exists but the server does not want to reveal that it exists. So 404 does not always mean “there is no page”.

404 is not among the codes the Prokso proxy answers with. If you see 404, the request passed through the proxy and reached the site, and the response was generated by the site itself.

Through a proxy, 404 is most often related to the site seeing a different country than you expect, or to an error in the URL that the program builds.

Causes

• A regional version of the site. Based on the IP country, the site redirects to another language or regional version where this page does not exist.
• The product or content is not available in this country. Some sites show 404 instead of an explanation if the content is not intended for the visitor's country.
• An error in the URL. An extra slash, wrong letter case, or a URL assembled from parts in a script with an error.
• The page was deleted or moved. The link is outdated, with or without a proxy.
• The site answers automated requests this way. A 404 response instead of 403 is allowed by the standard, and some sites use it.

How to fix it

1. Open the same URL without the proxy and compare the result.
2. Check which country the site sees: open My IP through the same proxy. If the country is wrong, choose the right one in the proxy generator, see the list of countries.
3. Trace the redirects: in a browser, on the Network tab of the developer tools; in curl, with the -L -v flags.
4. Check the URL character by character: letter case, slashes, parameters.
5. If 404 comes for pages that really exist and only through a proxy, also see the 403 error: the causes are often shared.

How to check that it works

Open the page in a browser through a proxy with the same country as in the program. If the page exists in the browser but the program gets 404, compare the URL and headers the program sends.

Two-minute diagnosis

First paste the line into the proxy checker. If the proxy works there, the cause is in your app or its settings. If not, test the line from a terminal:

curl -v -x "http://USERNAME:PASSWORD@gw.prokso.com:823" https://api.ipify.org

• A < HTTP/1.1 407 line right after CONNECT means the proxy answered. The name after the code, for example NO_USER, points to the cause.
• The proxy answered CONNECT with 200 and then another code arrived - the proxy works, and that answer came from the website.
• No answer at all, only a timeout - the connection never reached the proxy: check the host, port and network.