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HTTP Status Codes Explained in Plain English (2026)

By the IsItDown team · Updated 2026-10-12

404, 500, 503 — every code you'll actually encounter, translated into plain English with what to do next.

Every time your browser talks to a website, the server answers with a three-digit HTTP status code. Our checker shows you this code because it tells you why something failed. Here's what the common ones mean — no jargon.

2xx — Success

200 OK: everything worked. The page loaded normally. If you see 200 but the page looks broken, the problem is in the page's code or your browser, not the server.

3xx — Redirection

301 Moved Permanently / 302 Found: the address forwarded you elsewhere — totally normal (e.g. http → https). Our checker follows the whole redirect chain and shows every hop, because too many hops or a redirect loop will break a site.

4xx — Client errors (your request was the problem)

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400 Bad Request: the server couldn't understand the request — often a corrupted cookie; clear them. 401 Unauthorized / 403 Forbidden: you need to log in, or you're explicitly blocked (IP bans and geo-blocks show up as 403). 404 Not Found: the page doesn't exist — check the URL for typos; if you followed a link, the page was moved or deleted. 429 Too Many Requests: you're being rate-limited — slow down, wait a bit, try again.

5xx — Server errors (their problem, not yours)

500 Internal Server Error: the server crashed handling your request — vague, but always their bug. 502 Bad Gateway: the server's upstream (often a proxy like Cloudflare talking to the real server) got an invalid response. 503 Service Unavailable: the server is overloaded or down for maintenance — the classic “we're experiencing issues” code; waiting is the fix. 504 Gateway Timeout: the upstream server took too long — try again in a few minutes.

How to use this

When a site fails, run it through our checker and read the code: 4xx means look at your side (URL, login, cookies, rate limits); 5xx means wait it out or contact the site owner. That one distinction saves most of the guesswork in troubleshooting.

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