Error map
no "ssl_certificate" is defined for the "listen ... ssl" directive Nginx: [emerg] no "ssl_certificate" is defined for the "listen ... ssl" directive in /etc/nginx/sites-enabled/default:3
SSL / TLS · layer 2, Network
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_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.
Apache: AH02240: Server should be SSL-aware but has no certificate configured / SSLCertificateFile: file '/etc/ssl/x.crt' does not exist or is empty
Apache cannot find the certificate or key file named in its configuration, or `SSLEngine on` is set without any certificate.
Nginx: [warn] "ssl_stapling" ignored, no OCSP responder URL in the certificate "/etc/ssl/cert.pem"
OCSP stapling is enabled but the certificate (or chain file) contains no OCSP responder, so nginx can't staple a response.
Firefox: Secure Connection Failed — SSL received a record that exceeded the maximum permissible length. Error code: SSL_ERROR_RX_RECORD_TOO_LONG
Firefox sent a TLS handshake but received plain HTTP back — you used `https://` on a port that serves HTTP.
OpenSSL: SSL alert number 112 — tlsv1 unrecognized name
The server did not recognise the hostname sent in SNI and rejected the handshake (or an alert/warning is logged).
Nginx: [emerg] SSL_CTX_use_PrivateKey_file("/etc/ssl/server.key") failed (SSL: error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch)
The private key does not belong to the certificate configured in the server.
Let's Encrypt: Fetching http://example.com/.well-known/acme-challenge/token: Timeout during connect (likely firewall problem)
The ACME validation server could not reach your server on port 80 within the timeout.
Certbot: Could not automatically find a matching server block for example.com. Set the `server_name` directive to use the Nginx installer
Certbot's Nginx plugin could not find a `server` block whose `server_name` matches the domain you requested.
Nginx: [emerg] SSL_CTX_set_tmp_dh("/etc/ssl/dhparam.pem") failed (SSL: error:1401E0A8:SSL routines:... dh key too small)
The Diffie-Hellman parameters file is too weak (e.g. 512 or 768 bit) for the current OpenSSL security level.
Chrome: ERR_HTTP2_INADEQUATE_TRANSPORT_SECURITY — HTTP/2 requires a modern TLS cipher
The server speaks HTTP/2 but negotiated a TLS version or cipher that HTTP/2 forbids (blocklisted ciphers or TLS below 1.2).
Two steps away (29)
Cloudflare Error 525: SSL Handshake Failed
Cloudflare couldn’t complete a TLS handshake with your origin (SSL mode Full / Full strict).
javax.net.ssl.SSLHandshakeException: PKIX path building failed: unable to find valid certification path to requested target
Java doesn’t trust the server’s certificate chain (self-signed, corporate proxy CA, or missing intermediate).
QuotaExceededError: Failed to execute 'setItem' on 'Storage': Setting the value exceeded the quota
localStorage/sessionStorage is full (about 5 MB per origin) or storage is disabled.
ERR_TOO_MANY_REDIRECTS with Cloudflare (Flexible SSL redirect loop)
The page redirects to itself forever — classic cause: Cloudflare SSL mode “Flexible” while the origin redirects HTTP to HTTPS.
ERR_SSL_VERSION_OR_CIPHER_MISMATCH on a Cloudflare site (certificate not issued / multi-level subdomain)
Cloudflare has no edge certificate for the hostname — the Universal SSL cert is still pending, or the hostname is a second-level…
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…
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.
SSL Labs: Chain issues: Incomplete — Extra download (intermediate certificate missing)
The server sends only its own certificate and not the intermediate CA(s), so some clients cannot build a trusted chain.
curl (Windows Schannel): schannel: next InitializeSecurityContext failed: CRYPT_E_NO_REVOCATION_CHECK (0x80092012) - The revocation function was unable to check revocation for the certificate
Windows could not contact the CA's CRL/OCSP servers to check whether the certificate is revoked, so Schannel aborted.
Firefox: Peer's Certificate has expired. Error code: SEC_ERROR_EXPIRED_CERTIFICATE
Firefox found an expired certificate in the chain presented by the server.
Firefox: Websites prove their identity via certificates — the certificate is only valid for other names. Error code: SSL_ERROR_BAD_CERT_DOMAIN
The certificate does not include the hostname you typed.
OpenSSL: error:1408F10B:SSL routines:ssl3_get_record:wrong version number
The peer did not answer with a TLS record — you spoke TLS to a plain HTTP/SMTP port (or the reverse), or a proxy intervened.
OpenSSL: error:14094410:SSL routines:ssl3_read_bytes:sslv3 alert handshake failure (SSL alert number 40)
The server aborted the handshake with alert 40 — no acceptable parameters (cipher, signature algorithm, client certificate or SNI…
Java: javax.net.ssl.SSLHandshakeException: Received fatal alert: handshake_failure
The server rejected the Java client's TLS offer — no shared protocol/cipher, SNI issue or a required client certificate.
Python: ssl.SSLEOFError: EOF occurred in violation of protocol (_ssl.c:2396)
The server closed the TLS connection abruptly without a proper shutdown, usually because it rejected the handshake or dropped the…
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Nginx (or another server) can’t listen on the port because another process already holds it — often Apache, another Nginx, or a s…
Nginx: upstream timed out (110: Connection timed out) while reading response header from upstream
Nginx waited longer than proxy_read_timeout (60 s default) for the backend (app server, PHP-FPM) to respond, then returned 504.
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…
Cloudflare Error 1020: Access Denied
A Cloudflare firewall/WAF custom rule blocked the request — the visitor’s IP, country, user agent or request pattern matched a bl…
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.
connect: No route to host (EHOSTUNREACH)
The destination host isn’t reachable — it’s down, on another subnet without routing, or a firewall rejects with “host unreachable…
Let’s Encrypt / Certbot: Challenge failed for domain example.com — Invalid response from http://example.com/.well-known/acme-challenge/x: 404
Let’s Encrypt couldn’t verify you control the domain — the HTTP-01 challenge file wasn’t served, or DNS points elsewhere.
Certbot: Failed to renew certificate example.com with error — The following certs could not be renewed: /etc/letsencrypt/live/example.com/fullchain.pem (failure)
`certbot renew` failed for one or more certificates, so they will expire if you don't fix it.
Certbot: Problem binding to port 80: Could not bind to IPv4 or IPv6 (standalone authenticator)
`certbot --standalone` needs to listen on port 80 for the HTTP-01 challenge but another process (Nginx, Apache) already holds it.
OpenSSL: error:0A00018E:SSL routines::ca md too weak / error:140AB18F:SSL routines:SSL_CTX_use_certificate:ee key too small
OpenSSL's security level rejected a certificate signed with a weak hash (MD5/SHA-1) or with a small key (RSA < 2048).
Apache: [ssl:warn] AH01909: example.com:443:0 server certificate does NOT include an ID which matches the server name
Apache's SSL virtual host name does not match any name inside the certificate it loads.
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.
Let's Encrypt/CA: CAA record for example.com prevents issuance
The domain's DNS CAA records do not list the certificate authority you asked, so the CA must refuse.
Chrome: ERR_SSL_KEY_USAGE_INCOMPATIBLE — the certificate's key usage doesn't allow the negotiated cipher
The server's certificate Key Usage extension does not permit the key exchange used (typically an RSA certificate missing `keyEnci…
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