Error map
523 Cloudflare Error 523: Origin is unreachable
Cloudflare · layer 3, Edge & web server
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)
Cloudflare Error 522: Connection Timed Out
Cloudflare’s TCP connection to your origin timed out — the origin didn’t answer at all.
Cloudflare Error 521: Web Server Is Down
Cloudflare couldn’t connect to your origin — the connection was refused.
Cloudflare HTTP 530 (with Error 1016 Origin DNS error / 1033 tunnel error)
Cloudflare returns 530 together with a 1xxx error; the 1xxx code (usually 1016 or 1033) tells you the real cause.
Cloudflare Error 1002: DNS points to Prohibited IP / Restricted
A record points to a private, reserved or Cloudflare IP that Cloudflare won’t proxy to.
Cloudflare Error 1000: DNS points to prohibited IP
A proxied DNS record points at a Cloudflare IP address, creating a loop.
Cloudflare Error 1016: Origin DNS error
Cloudflare can’t resolve the origin hostname your DNS record points to (usually a CNAME target).
Cloudflare Error 1033: Argo Tunnel error (Cloudflare Tunnel not connected)
The hostname routes to a Cloudflare Tunnel, but no healthy cloudflared connector is running for it.
cloudflared: Unable to reach the origin service. The service may be down or it may not be responding to traffic from cloudflared (502)
The tunnel is connected, but cloudflared can’t reach your local service at the address in the ingress rule.
Cloudflare Error 1001: DNS resolution error
Cloudflare received the request but the hostname isn’t set up on Cloudflare (or the domain was just added and not active yet).
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.
Firefox: Hmm. We’re having trouble finding that site. / Server not found (DNS_PROBE or NS_ERROR_UNKNOWN_HOST)
Firefox could not resolve the website’s hostname to an IP address — a typo, a DNS problem or no internet.
Two steps away (31)
HTTP 504 Gateway Timeout
A proxy or gateway waited too long for the upstream server to respond and gave up.
Cloudflare Error 520: Web Server Returned an Unknown Error
Cloudflare connected to your origin, but the origin returned an empty, unknown or invalid response.
Cloudflare Error 524: A Timeout Occurred
Cloudflare connected to the origin, but the origin didn’t send an HTTP response within 100 seconds.
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.
Cloudflare Error 525: SSL Handshake Failed
Cloudflare couldn’t complete a TLS handshake with your origin (SSL mode Full / Full strict).
java.net.ConnectException: Connection refused
Nothing is listening at the host:port the Java client connected to.
Cloudflare Error 1003: Direct IP access not allowed
The request went to a Cloudflare IP address directly (or with a Host header for a domain not on Cloudflare).
net::ERR_NAME_NOT_RESOLVED (This site can't be reached — server IP address could not be found)
DNS couldn’t resolve the hostname in the browser.
cURL error 6: Could not resolve host: api.example.com
PHP cURL couldn’t resolve the hostname via DNS.
ACM certificate stuck in Pending validation
ACM is waiting to see the DNS (or email) validation record — it wasn’t created, was created in the wrong DNS zone, or has a typo.
HTTP 413 Content Too Large (Request Entity Too Large)
The request body is bigger than the server is willing to accept — usually a file upload over the configured limit.
WordPress: Error Establishing a Database Connection
WordPress can’t connect to its MySQL/MariaDB database with the credentials in wp-config.php, or the database server is down.
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.
Cloudflare-branded 502 Bad Gateway / 504 Gateway Timeout ("cloudflare" footer)
A plain-looking 502/504 page with “cloudflare” at the bottom comes from Cloudflare’s network itself (or an origin response it cou…
Cloudflare Error 1004: Host Not Configured to Serve Web Traffic
The DNS record was just created or changed and Cloudflare hasn’t propagated it yet — or Spectrum/non-HTTP ports are involved.
Cloudflare Error 1014: CNAME Cross-User Banned
Your DNS CNAME points to a hostname in another Cloudflare account, which Cloudflare blocks by default for security.
Cloudflare Error 1200: Cache connection limit
Too many requests are queued at Cloudflare for the origin — the origin is slow and connections pile up.
NET::ERR_CERT_AUTHORITY_INVALID with a Cloudflare Origin Certificate (record not proxied)
Cloudflare Origin CA certificates are only trusted by Cloudflare — visitors reaching the origin directly (grey-cloud record, dire…
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.
fatal: unable to access 'https://github.com/…': Could not resolve host: github.com
DNS lookup for the Git host failed from this machine.
java.net.UnknownHostException: api.example.com
DNS resolution failed for the hostname.
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.
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.
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.
Cloudflare Error 1018: Could not find host
The hostname isn’t found on Cloudflare — the zone was recently added/removed, or the record doesn’t exist yet.
Cloudflare Error 1023: Could not find host
Cloudflare can’t find the host — typically a zone that’s inactive or a custom hostname/SSL for SaaS not set up.
Cloudflare Error 1034: Edge IP Restricted
The DNS record points to a Cloudflare IP not assigned to your zone — typically an A record pointing to an old Cloudflare IP or an…
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