Articles & Guides
Useful resources for web developers and system administrators
Found 33 · HTTP · Reset
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Cloudflare Error 524 A Timeout Occurred: Causes and Fixes
Error 524 means your origin accepted Cloudflare's connection but sent no response within 125 seconds. Find the slow request, fix it, and compare codes 520–526.
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HTTP 413 Request Entity Too Large: Which Layer Rejected It
Five components each enforce their own body-size limit, and one of them returns an empty form instead of a 413. Find the narrowest gate before editing configs.
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Nginx 499 Client Closed Request: What It Means and What to Fix
499 is a log entry, not a status code, and nobody ever receives one. The duration distribution splits timeout misconfiguration from a genuinely slow upstream.
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ERR_HTTP2_PROTOCOL_ERROR: Why It Is Almost Never Your Browser
Chrome aborts on an invalid HTTP/2 frame, so cache and browser tips miss the cause. One protocol comparison separates server, network and client in seconds.
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Cloudflare Errors 520-530: What Each Says About Your Origin
Cloudflare errors 520, 521, 522, 523, 524, 525, 526 and 530 explained: which layer each code blames, and the exact command that confirms the cause.
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How to Check a Site's Redirect Chain in a Minute
How to check a redirect chain and a link’s final address: a tool, curl, DevTools. What 301/302/307/308 mean and which chains are dangerous.
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HTTP 451 Unavailable For Legal Reasons Explained
What HTTP 451 means under RFC 7725, how it differs from 403, who returns it, its link to Roskomnadzor blocks, and how to serve 451 with the blocked-by header.
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401 Unauthorized Error: What It Means and How to Fix It
401 Unauthorized means missing, expired or wrong credentials. Read the WWW-Authenticate challenge and fix it in curl, Postman, nginx and Apache.
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400 Bad Request: How to Fix It in Chrome, nginx and APIs
400 Bad Request means the server refused a malformed request. Fix it in Chrome, Edge, Firefox or Safari, raise nginx header limits, debug Postman and APIs.
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Cloudflare 522 Connection Timed Out Fix
Cloudflare error 522 Connection Timed Out means your origin server did not answer in time. Diagnose the origin, check the firewall, use curl, and fix it.