Error map
ERR_PROXY_CONNECTION_FAILED Chrome: Unable to connect to the proxy server. ERR_PROXY_CONNECTION_FAILED
Browser · layer 1, On your device
Centre: this error. First ring: errors it is linked with (9). 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 (9)
Chrome: No internet — There is something wrong with the proxy server. ERR_TUNNEL_CONNECTION_FAILED
Chrome asked a proxy to open a tunnel (HTTPS CONNECT) to the website and the proxy refused or could not reach it.
0x80070035: The network path was not found (System error 53)
Windows can’t reach the shared folder — name resolution, SMB settings, firewall or network discovery is preventing it.
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.
Chrome: This site can’t be reached — ERR_NETWORK_ACCESS_DENIED (blocked by firewall or antivirus)
Something on your computer — usually the Windows firewall or antivirus — denied Chrome network access.
HTTP 407 Proxy Authentication Required
A proxy between you and the server requires credentials before it will forward your request.
HTTP 417 Expectation Failed
The server or a proxy can’t meet the Expect header in the request — almost always Expect: 100-continue.
Chrome: No internet — ERR_INTERNET_DISCONNECTED (You are not connected to the internet)
Chrome sees no working network connection on the device, so it cannot load any page.
HTTP 511 Network Authentication Required
A captive portal (hotel, airport, office Wi-Fi) is intercepting your traffic until you log in or accept its terms.
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 (26)
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.
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…
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 408 Request Timeout
The server closed the connection because the client took too long to send the complete request.
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.
Error: getaddrinfo ENOTFOUND host / Name or service not known
DNS lookup for the hostname failed — the name is wrong, doesn’t exist, or this machine can’t resolve it.
Chrome: This site can’t be reached — The webpage at https://… might be temporarily down. ERR_ADDRESS_UNREACHABLE
The computer has no route to the server’s IP address — often an IPv6 problem, a wrong local-network address, or a VPN routing iss…
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: The connection was aborted — ERR_CONNECTION_ABORTED (software on your computer caused it)
The connection was aborted on your own computer — usually antivirus, a firewall or VPN software terminating it.
Gradle: Could not resolve all files for configuration / Could not resolve dependency
Gradle couldn’t download a dependency — wrong coordinates/version, missing repository, offline mode, or network/proxy issues.
HTTP 401 Unauthorized
The request has no valid authentication credentials — you need to log in or send a valid token.
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 400 Bad Request
The server could not understand the request because its syntax, headers or body are malformed or invalid.
HTTP 411 Length Required
The server refuses a request with a body but no Content-Length header.
HTTP 428 Precondition Required
The server requires a conditional request (If-Match / If-Unmodified-Since) to prevent lost updates, and you didn’t send one.
Cloudflare Error 521: Web Server Is Down
Cloudflare couldn’t connect to your origin — the connection was refused.
Cloudflare Error 522: Connection Timed Out
Cloudflare’s TCP connection to your origin timed out — the origin didn’t answer at all.
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…
SyntaxError: Unexpected token < in JSON at position 0
`JSON.parse()` / `response.json()` received something that isn’t JSON — very often an HTML error page.
fatal: early EOF — fatal: index-pack failed
A clone or fetch was cut off mid-transfer.
java.net.ConnectException: Connection refused
Nothing is listening at the host:port the Java client connected to.
net::ERR_BLOCKED_BY_CLIENT
A browser extension (ad blocker, privacy tool) blocked the request.
net::ERR_CONNECTION_REFUSED (This site can't be reached — refused to connect)
The browser reached the host but nothing was listening on that port.
NET::ERR_CERT_AUTHORITY_INVALID (Your connection is not private)
The site’s certificate isn’t signed by a CA the browser trusts — self-signed, missing intermediates, or intercepted by a proxy.
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