Error map
Challenge failed for domain Let’s Encrypt / Certbot: Challenge failed for domain example.com — Invalid response from http://example.com/.well-known/acme-challenge/x: 404
SSL / TLS · layer 2, Network
Centre: this error. First ring: errors it is linked with (7). 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 (7)
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.
NET::ERR_CERT_COMMON_NAME_INVALID: Your connection is not private (certificate is for a different domain)
The certificate presented doesn’t include the hostname you visited — e.g. visiting www.example.com with a certificate only for ex…
Provisioning profile "x" doesn't include signing certificate "Apple Development: Name (ID)"
The profile was created with a different certificate than the one installed in your keychain.
OpenSSL: unable to load certificate / PEM routines:get_name:no start line (key values mismatch)
OpenSSL (or Nginx/Apache) couldn’t read the certificate or key — wrong file format, wrong file, or the key doesn’t match the cert…
Chrome: This site can’t provide a secure connection — uses an unsupported protocol. ERR_SSL_VERSION_OR_CIPHER_MISMATCH
The browser and the server could not agree on a TLS version or cipher — the server is too old or misconfigured, or the browser is.
Chrome: Your connection is not private — NET::ERR_CERT_REVOKED (the certificate was revoked)
The site’s TLS certificate has been revoked by the certificate authority, so browsers refuse to trust it.
Firefox: Warning: Potential Security Risk Ahead — SEC_ERROR_UNKNOWN_ISSUER (certificate not trusted)
Firefox does not trust the authority that issued the site's certificate — a self-signed certificate, a missing intermediate, or a…
Two steps away (18)
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 525: SSL Handshake Failed
Cloudflare couldn’t complete a TLS handshake with your origin (SSL mode Full / Full strict).
NET::ERR_CERT_DATE_INVALID (certificate expired)
The site’s certificate has expired (or isn’t valid yet) — or the device clock is wrong.
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.
Error [ERR_TLS_CERT_ALTNAME_INVALID]: Hostname/IP does not match certificate's altnames
The server’s certificate doesn’t cover the hostname you connected to.
Xcode: No signing certificate "iOS Development" found
Xcode can’t find a valid code-signing certificate + private key for the selected team in your keychain.
Provisioning profile "x" doesn't include the currently selected device
The development profile doesn’t list this iPhone’s UDID, so Xcode can’t install the build on it.
Signing for "App" requires a development team. Select a development team in the Signing & Capabilities editor
No Apple developer team is selected for the target, so Xcode can’t sign the app.
Error: error:0308010C:digital envelope routines::unsupported
An old build tool (webpack 4, old react-scripts) uses a hash algorithm that OpenSSL 3 in Node 17+ disables.
Nginx: nginx: [emerg] unknown directive "x" in /etc/nginx/sites-enabled/x:12 — configuration file test failed
Nginx found a directive it doesn’t know — a typo, a missing semicolon on the previous line, a directive from a module that isn’t…
ERR_SSL_PROTOCOL_ERROR (This site can't provide a secure connection)
The browser couldn’t negotiate TLS — the server sent an invalid response, often plain HTTP on the HTTPS port.
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.
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: Connection not secure — ERR_SSL_OBSOLETE_VERSION (old TLS 1.0/1.1)
The server only supports an outdated TLS version that current browsers no longer allow.
Chrome: You cannot visit example.com right now because the website uses HSTS (NET::ERR_CERT_… no bypass)
The site told browsers to use only valid HTTPS (HSTS), so Chrome hides the "Proceed anyway" link when its certificate has any pro…
Firefox: Secure Connection Failed — SSL_ERROR_NO_CYPHER_OVERLAP (no common cipher)
Firefox and the server share no TLS cipher suite, so the secure handshake cannot even start.
Firefox: The page isn’t redirecting properly — Firefox has detected that the server is redirecting the request in a way that will never complete
Firefox's wording for a redirect loop (Chrome calls it ERR_TOO_MANY_REDIRECTS).
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.
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