Error map
kex_exchange_identification kex_exchange_identification: Connection closed by remote host
Git · layer 7, Build & delivery
Centre: this error. First ring: errors it is linked with (12). 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 (12)
ERR_CONNECTION_TIMED_OUT: This site can’t be reached — example.com took too long to respond
The browser waited for the server but got no response — the server is down/unreachable, a firewall drops traffic, or DNS points t…
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.
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.
Site Health: The REST API encountered an error / Your site could not complete a loopback request (cURL error 28)
WordPress couldn’t call itself over HTTP — needed for the block editor, cron, plugin/theme editors and Site Health.
Error: socket hang up / read ECONNRESET
The other side closed the TCP connection abruptly while your client was still using it.
fatal: unable to access 'https://github.com/…': Could not resolve host: github.com
DNS lookup for the Git host failed from this machine.
fatal: early EOF — fatal: index-pack failed
A clone or fetch was cut off mid-transfer.
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.
gRPC Error: 14 UNAVAILABLE: No connection established / failed to connect to all addresses
The gRPC client couldn’t reach the server — wrong address/port, TLS vs plaintext mismatch, server down, or a proxy that doesn’t s…
Firebase Auth: auth/network-request-failed — A network AuthError (such as timeout, interrupted connection or unreachable host) has occurred
The Firebase Auth SDK couldn’t reach Google’s servers — offline, blocked by an extension/firewall, or (on Android emulators) miss…
SSL error: tlsv1 alert protocol version / unsupported protocol / no protocols available
The client and server couldn’t agree on a TLS version or cipher, so the HTTPS handshake failed before any HTTP was exchanged.
ssh: connect to host x port 22: Connection refused
The server answered, but nothing is listening on the SSH port — sshd isn’t running, it uses another port, or a firewall actively…
Two steps away (36)
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 504 Gateway Timeout
A proxy or gateway waited too long for the upstream server to respond and gave up.
Cloudflare Error 522: Connection Timed Out
Cloudflare’s TCP connection to your origin timed out — the origin didn’t answer at all.
SSL: CERTIFICATE_VERIFY_FAILED / unable to get local issuer certificate
The client couldn’t verify the server’s TLS certificate chain, so it refused the HTTPS connection.
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…
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.
error: RPC failed; HTTP 400 curl 22 / curl 92 HTTP/2 stream was not closed cleanly — the remote end hung up unexpectedly
A large HTTPS push/clone broke mid-transfer — size limits, proxies or flaky HTTP/2.
WordPress: Updating failed. The response is not a valid JSON response.
The block editor saved via the REST API but got HTML or an error page back — broken permalinks, a security plugin/WAF, or PHP out…
ssh: connect to host github.com port 22: Connection timed out
Outbound SSH on port 22 is blocked (firewall, corporate or public Wi-Fi).
java.net.ConnectException: Connection refused
Nothing is listening at the host:port the Java client connected to.
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.
Too many open files (EMFILE)
The process hit its file-descriptor limit — sockets, files and pipes all count.
java.net.UnknownHostException: api.example.com
DNS resolution failed for the hostname.
fatal: No url found for submodule path 'x' in .gitmodules
A submodule entry exists in the index but its URL is missing from .gitmodules.
Error [ERR_STREAM_PREMATURE_CLOSE]: Premature close
A stream ended or was destroyed before it finished — often a client disconnect or upstream aborting a download.
npm ERR! code ENOTFOUND — request to https://registry.npmjs.org/x failed, reason: getaddrinfo ENOTFOUND registry.npmjs.org
npm couldn’t resolve the registry hostname.
Get "https://registry-1.docker.io/v2/": net/http: request canceled while waiting for connection (Client.Timeout exceeded)
Docker couldn’t reach the registry in time — a network, DNS, proxy or firewall problem between your machine and the registry.
dial tcp: lookup registry-1.docker.io: no such host / Temporary failure in name resolution during docker build
DNS isn’t working for the Docker daemon or inside build containers, so pulls and package downloads fail.
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.
Windows Error 0x80070005 (E_ACCESSDENIED): Access is denied
Windows refused an operation because the account or process lacks permission — seen in Windows Update, installers, Task Scheduler…
java.net.SocketException: Connection reset
The remote side closed the TCP connection abruptly while Java was reading or writing.
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_ABORTED 404 (Not Found)
The browser cancelled the request — often because it returned an error (404) or the page navigated away.
AbortError: The user aborted a request. / signal is aborted without reason
A fetch was cancelled through an AbortController (or the browser cancelled it).
WebSocket connection to 'wss://x' failed
The browser couldn’t open (or keep) a WebSocket connection.
MySQL ERROR 2003 (HY000): Can't connect to MySQL server on 'host:3306' (111)
The client couldn’t reach MySQL over TCP — server down, wrong host/port, firewall, or MySQL bound to localhost only.
TypeError: fetch failed (cause: ConnectTimeoutError / ECONNREFUSED / UND_ERR)
Node’s built-in fetch (undici) couldn’t complete the request; the real reason is in error.cause.
Mixed Content: The page was loaded over HTTPS, but requested an insecure resource
An HTTPS page tried to load a script, API or image over plain HTTP, and the browser blocked (or warned about) it.
CLEARTEXT communication to host not permitted by network security policy
Android 9+ blocks plain `http://` requests by default; the app tried to call a non-HTTPS URL.
App Transport Security has blocked a cleartext HTTP resource load
iOS blocked an `http://` request (or a weak-TLS HTTPS one) because App Transport Security requires secure connections.
ssh: connect to host x port 22: Connection timed out
SSH packets get no reply — a firewall/security group drops them, the server is off, or the IP is wrong.
WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! (ssh host key changed)
The server’s SSH host key differs from the one saved in ~/.ssh/known_hosts — usually because the server was rebuilt or the IP was…
WARNING: UNPROTECTED PRIVATE KEY FILE! Permissions 0644 for 'key.pem' are too open
SSH refuses to use a private key that other users can read; it must be readable only by you (chmod 600).
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