Error map
ERR_EMPTY_RESPONSE Chrome: This page isn’t working — example.com didn’t send any data. ERR_EMPTY_RESPONSE
Browser · layer 1, On your device
Centre: this error. First ring: errors it is linked with (10). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (10)
ERR_CONNECTION_RESET: This site can’t be reached — The connection was reset
The connection to the website was cut off mid-way — by the server, a firewall/antivirus, a VPN/proxy, or network equipment.
HTTP 502 Bad Gateway
A proxy or gateway (Nginx, load balancer, CDN) got an invalid response — or no response — from the upstream server behind it.
Nginx 444 No Response (connection closed without response)
An Nginx-specific code: the server deliberately closed the connection without sending anything — a rule is dropping the request.
Chrome: This page isn’t working — example.com redirected you too many times. ERR_TOO_MANY_REDIRECTS
The page keeps redirecting to itself or in a loop, so the browser gives up after about 20 redirects.
Chrome: This site can’t be reached — example.com unexpectedly closed the connection. ERR_CONNECTION_CLOSED
The server closed the connection before finishing the TLS handshake or sending a response — typical for HTTP/HTTPS port mix-ups,…
Chrome: This page isn’t working — example.com is unable to handle this request. ERR_HTTP2_PROTOCOL_ERROR
The HTTP/2 connection broke a protocol rule — a server, proxy or CDN sent an invalid or oversized frame/header, or closed the str…
Chrome DevTools: net::ERR_INCOMPLETE_CHUNKED_ENCODING 200 (OK) — response cut off midway
The server started sending a chunked response with status 200 and then stopped before the final chunk, so Chrome reports the tran…
Chrome DevTools: net::ERR_CONTENT_LENGTH_MISMATCH — body shorter than the Content-Length header
The server promised a number of bytes in `Content-Length` and sent a different number, so Chrome treats the download as corrupted.
Chrome: This page isn’t working — sent an invalid response. ERR_CONTENT_DECODING_FAILED
The response claims to be compressed (gzip/brotli) but cannot be decompressed — it was double-compressed, truncated or not compre…
Browser: This network requires you to sign in — captive portal (hotel, airport, café Wi-Fi) blocking HTTPS sites
The Wi-Fi needs a login or acceptance page first; until you complete it, secure sites fail with certificate or connection errors.
Two steps away (27)
Error: connect ECONNREFUSED 127.0.0.1:5432
Nothing is listening at that host:port — the target service is down or you’re connecting to the wrong address.
HTTP 407 Proxy Authentication Required
A proxy between you and the server requires credentials before it will forward your request.
HTTP 408 Request Timeout
The server closed the connection because the client took too long to send the complete request.
HTTP 500 Internal Server Error
The server hit an unexpected condition — usually an unhandled exception or misconfiguration in the application.
HTTP 503 Service Unavailable
The server is temporarily unable to handle the request — overloaded, in maintenance, or has no healthy backends.
HTTP 504 Gateway Timeout
A proxy or gateway waited too long for the upstream server to respond and gave up.
HTTP 403 Forbidden
The server understood the request but refuses to authorize it — you (or the server process) are not allowed to access this resour…
HTTP 499 Client Closed Request (Nginx)
Nginx-specific code logged when the client disconnected before the server finished responding.
FastCGI sent in stderr: "Primary script unknown"
Nginx passed a script path to PHP-FPM that PHP-FPM couldn’t find — usually a wrong SCRIPT_FILENAME or root.
HTTP 301 Moved Permanently
The resource has a new permanent URL; clients and search engines should use the address in the Location header from now on.
HTTP 302 Found (Temporary Redirect)
The resource is temporarily at another URL; clients should keep using the original URL for future requests.
HTTP 303 See Other
A redirect telling the client to fetch the result from another URL with GET — used after a form POST so refreshing doesn’t resubm…
Cloudflare Error 525: SSL Handshake Failed
Cloudflare couldn’t complete a TLS handshake with your origin (SSL mode Full / Full strict).
Cloudflare Error 526: Invalid SSL Certificate
With SSL mode Full (strict), the origin’s certificate is expired, self-signed, or doesn’t match the hostname.
Chrome: Your connection was interrupted — A network change was detected. ERR_NETWORK_CHANGED
The device switched networks (Wi-Fi to mobile data, VPN on/off, IP renewed) while the page was loading, so the browser aborted th…
HTTP 431 Request Header Fields Too Large
The request headers — almost always cookies — exceed the server’s size limit.
HTTP 505 HTTP Version Not Supported
The server doesn’t support the HTTP protocol version used in the request.
HTTP 100 Continue
An interim response telling the client to go ahead and send the request body — normal when the client sent Expect: 100-continue.
PHP Fatal error: Maximum execution time of 30 seconds exceeded
The script ran longer than `max_execution_time` and PHP stopped it.
Chrome: This site can’t be reached — server IP address could not be found. DNS_PROBE_FINISHED_NXDOMAIN
The DNS server answered that the domain name does not exist (NXDOMAIN) — a typo, an expired or unregistered domain, a missing DNS…
Chrome: No internet — DNS_PROBE_FINISHED_NO_INTERNET (DNS probe finished, no internet)
Chrome’s built-in DNS probe could not reach any DNS server, so the device effectively has no working internet or DNS.
HTTP 411 Length Required
The server refuses a request with a body but no Content-Length header.
HTTP 406 Not Acceptable
The server can’t produce a response in any format listed in the request’s Accept headers.
Chrome: Aw, Snap! Something went wrong while displaying this webpage. Error code: STATUS_ACCESS_VIOLATION / SIGILL / Out of Memory
A Chrome tab crashed — out of memory, a faulty extension, a graphics/driver issue or a very heavy page.
TypeError: Failed to fetch / NetworkError when attempting to fetch resource
The browser couldn’t complete the request at the network level — CORS, DNS, offline, blocked mixed content, or the server refused…
API Request Timed Out (ETIMEDOUT / ReadTimeout / timeout of 30000ms exceeded)
The client gave up waiting — either for the connection to open or for the response to arrive.
Error: socket hang up / read ECONNRESET
The other side closed the TCP connection abruptly while your client was still using it.
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