Error map

gRPC: Ssl handshake failed / authentication handshake failed gRPC: rpc error: code = Unavailable desc = connection error: desc = "transport: authentication handshake failed: x509: certificate signed by unknown authority"

SSL / TLS · layer 2, Network

Open the full error page →

Centre: this error. First ring: errors it is linked with (8). 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.

1 · On your device 2 · Network 4 · Application & API
gRPC: Ssl handshake failed / authentication handshake failed — gRPC: rpc error: code = Unavailable desc = connection error: desc = "transport: authentication handshake failed: x509: certificate signed by unknown authority" (SSL / TLS)gRPC: Ssl h…Received fatal alert: handshake_failure — Java: javax.net.ssl.SSLHandshakeException: Received fatal alert: handshake_failure (SSL / TLS)Received fatal aler…Certificate pinning failure! — Android/OkHttp: javax.net.ssl.SSLPeerUnverifiedException: Certificate pinning failure! Peer certificate chain: sha256/... Pinned certificates for api.example.com (SSL / TLS)Certificate pinning…x509: certificate signed by unknown authority — Go: x509: certificate signed by unknown authority (Go)x509: certificate s…x509: certificate is valid for X, not Y — Go: x509: certificate is valid for www.example.com, not api.example.com (Go)x509: certificate i…sslv3 alert handshake failure — OpenSSL: error:14094410:SSL routines:ssl3_read_bytes:sslv3 alert handshake failure (SSL alert number 40) (SSL / TLS)sslv3 alert handsha…SSL routines: wrong version number — OpenSSL: error:1408F10B:SSL routines:ssl3_get_record:wrong version number (SSL / TLS)SSL routines: wrong…tlsv1 unrecognized name (SNI) — OpenSSL: SSL alert number 112 — tlsv1 unrecognized name (SSL / TLS)tlsv1 unrecognized …EOF occurred in violation of protocol — Python: ssl.SSLEOFError: EOF occurred in violation of protocol (_ssl.c:2396) (SSL / TLS)EOF occurred in vio…PKIX path building failed — javax.net.ssl.SSLHandshakeException: PKIX path building failed: unable to find valid certification path to requested target (Java)PKIX path building …tlsv1 alert protocol version — OpenSSL: error:14094410 / SSL alert number 70 — tlsv1 alert protocol version (SSL / TLS)tlsv1 alert protoco…No subject alternative names present — Java: javax.net.ssl.SSLHandshakeException: No subject alternative names matching IP address 10.0.0.5 found (SSL / TLS)No subject alternat…HandshakeException: CERTIFICATE_VERIFY_FAILED — Dart: HandshakeException: Handshake error in client (OS Error: CERTIFICATE_VERIFY_FAILED: unable to get local issuer certificate) (Flutter / Dart)HandshakeException:…SSLCertificateFile: file does not exist — Apache: AH02240: Server should be SSL-aware but has no certificate configured / SSLCertificateFile: file '/etc/ssl/x.crt' does not exist or is empty (SSL / TLS)SSLCertificateFile:…Timeout during connect (likely firewall problem) — Let's Encrypt: Fetching http://example.com/.well-known/acme-challenge/token: Timeout during connect (likely firewall problem) (SSL / TLS)Timeout during conn…cannot assign to struct field m[k].f in map — Go: cannot assign to struct field users["bob"].Age in map (Go)cannot assign to st…assignment mismatch: 1 variable but f returns 2 values — Go: assignment mismatch: 1 variable but os.Open returns 2 values (Go)assignment mismatch…cannot find package in any of GOROOT / GOPATH — Go: cannot find package "github.com/pkg/errors" in any of: /usr/local/go/src/github.com/pkg/errors (from $GOROOT) /go/src/github.com/pkg/errors (from $GOPATH) (Go)cannot find package…NET::ERR_CERT_COMMON_NAME_INVALID — NET::ERR_CERT_COMMON_NAME_INVALID: Your connection is not private (certificate is for a different domain) (SSL / TLS)NET::ERR_CERT_COMMO…panic: assignment to entry in nil map — Go: panic: assignment to entry in nil map (Go)panic: assignment t…listen tcp :8080: bind: address already in use — Go: listen tcp :8080: bind: address already in use (Go)listen tcp :8080: b…cURL error 35 — cURL error 35: OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to host:443 (PHP)cURL error 35SSL_ERROR_NO_CYPHER_OVERLAP — Firefox: Secure Connection Failed — SSL_ERROR_NO_CYPHER_OVERLAP (no common cipher) (Browser)SSL_ERROR_NO_CYPHER…unable to get local issuer certificate — OpenSSL: error:num=20:unable to get local issuer certificate / SSL: CERTIFICATE_VERIFY_FAILED (SSL / TLS)unable to get local…ERR_SSL_PROTOCOL_ERROR — ERR_SSL_PROTOCOL_ERROR (This site can't provide a secure connection) (JavaScript)ERR_SSL_PROTOCOL_ER…SSL: WRONG_VERSION_NUMBER (SMTP port) — SMTP: [SSL: WRONG_VERSION_NUMBER] wrong version number — SMTP over SSL on a STARTTLS port (Email / SMTP)SSL: WRONG_VERSION_…verify error:num=10: certificate has expired — OpenSSL: verify error:num=10:certificate has expired — notAfter=Jan 1 00:00:00 2025 GMT (SSL / TLS)verify error:num=10…SSL_ERROR_BAD_CERT_DOMAIN — Firefox: Websites prove their identity via certificates — the certificate is only valid for other names. Error code: SSL_ERROR_BAD_CERT_DOMAIN (SSL / TLS)SSL_ERROR_BAD_CERT_…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)no "ssl_certificate…CERTIFICATE_VERIFY_FAILED — SSL: CERTIFICATE_VERIFY_FAILED / unable to get local issuer certificate (API)CERTIFICATE_VERIFY_…HTTPSConnectionPool: Max retries exceeded (SSLError) — Python requests: HTTPSConnectionPool(host='api.example.com', port=443): Max retries exceeded with url: /v1 (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] ...'))) (SSL / TLS)HTTPSConnectionPool…

Directly related (8)

Received fatal alert: handshake_failureSSL / TLS

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.

Certificate pinning failure!SSL / TLS

Android/OkHttp: javax.net.ssl.SSLPeerUnverifiedException: Certificate pinning failure! Peer certificate chain: sha256/... Pinned certificates for api.example.com

The app's pinned certificate/public-key hash does not match the one the server presented, so OkHttp blocked the request.

x509: certificate signed by unknown authorityGo

Go: x509: certificate signed by unknown authority

The Go TLS client does not trust the CA that signed the server's certificate.

x509: certificate is valid for X, not YGo

Go: x509: certificate is valid for www.example.com, not api.example.com

The server's certificate does not list the hostname you connected to (SAN mismatch), or it has expired.

sslv3 alert handshake failureSSL / TLS

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…

SSL routines: wrong version numberSSL / TLS

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.

tlsv1 unrecognized name (SNI)SSL / TLS

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).

EOF occurred in violation of protocolSSL / TLS

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…

Two steps away (22)

PKIX path building failedJava

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).

tlsv1 alert protocol versionSSL / TLS

OpenSSL: error:14094410 / SSL alert number 70 — tlsv1 alert protocol version

The server rejected the TLS version your client offered, because it requires a newer (or older) protocol.

No subject alternative names presentSSL / TLS

Java: javax.net.ssl.SSLHandshakeException: No subject alternative names matching IP address 10.0.0.5 found

Java checks the hostname against the certificate's SANs and found no matching entry (for DNS names or IPs).

HandshakeException: CERTIFICATE_VERIFY_FAILEDFlutter / Dart

Dart: HandshakeException: Handshake error in client (OS Error: CERTIFICATE_VERIFY_FAILED: unable to get local issuer certificate)

The app refused the server's TLS certificate because it is self-signed, expired, missing intermediates, or the device clock/CA st…

SSLCertificateFile: file does not existSSL / TLS

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.

Timeout during connect (likely firewall problem)SSL / TLS

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.

cannot assign to struct field m[k].f in mapGo

Go: cannot assign to struct field users["bob"].Age in map

Map values are not addressable, so you cannot modify a field of a struct stored directly in a map.

assignment mismatch: 1 variable but f returns 2 valuesGo

Go: assignment mismatch: 1 variable but os.Open returns 2 values

The number of variables on the left does not match the number of values the function returns.

cannot find package in any of GOROOT / GOPATHGo

Go: cannot find package "github.com/pkg/errors" in any of: /usr/local/go/src/github.com/pkg/errors (from $GOROOT) /go/src/github.com/pkg/errors (from $GOPATH)

Go could not locate an imported package — it is not downloaded, the module is not initialised, or GOPATH mode is in effect.

NET::ERR_CERT_COMMON_NAME_INVALIDSSL / TLS

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…

panic: assignment to entry in nil mapGo

Go: panic: assignment to entry in nil map

You wrote to a map that was declared but never initialised.

listen tcp :8080: bind: address already in useGo

Go: listen tcp :8080: bind: address already in use

The port your Go server wants is already taken by another process (or a previous instance of your app).

cURL error 35PHP

cURL error 35: OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to host:443

The TLS handshake failed — protocol/cipher mismatch, a proxy interfering, or the server closed the connection.

SSL_ERROR_NO_CYPHER_OVERLAPBrowser

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.

unable to get local issuer certificateSSL / TLS

OpenSSL: error:num=20:unable to get local issuer certificate / SSL: CERTIFICATE_VERIFY_FAILED

The client could not build a chain from the server's certificate to a CA it trusts — the issuer is missing locally or the server…

ERR_SSL_PROTOCOL_ERRORJavaScript

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: WRONG_VERSION_NUMBER (SMTP port)Email / SMTP

SMTP: [SSL: WRONG_VERSION_NUMBER] wrong version number — SMTP over SSL on a STARTTLS port

Your client tried to start TLS immediately on a port where the server speaks plain SMTP first (or the reverse), so the handshake…

verify error:num=10: certificate has expiredSSL / TLS

OpenSSL: verify error:num=10:certificate has expired — notAfter=Jan 1 00:00:00 2025 GMT

OpenSSL's verification found a certificate in the chain whose validity period has ended.

SSL_ERROR_BAD_CERT_DOMAINSSL / TLS

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.

no "ssl_certificate" is defined for the "listen ... ssl" directiveSSL / TLS

Nginx: [emerg] no "ssl_certificate" is defined for the "listen ... ssl" directive in /etc/nginx/sites-enabled/default:3

A server block listens with `ssl` but has no `ssl_certificate` and `ssl_certificate_key`.

CERTIFICATE_VERIFY_FAILEDAPI

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.

HTTPSConnectionPool: Max retries exceeded (SSLError)SSL / TLS

Python requests: HTTPSConnectionPool(host='api.example.com', port=443): Max retries exceeded with url: /v1 (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] ...')))

The `requests` call failed during the TLS step and exhausted its retries; the real reason is in the nested SSLError text.

Map another error

Popular: 500403400ORA-009331064Critical errorFileNotFoundException assemblyTypeError