What This Error Means
npm received a self-signed certificate at the top of the TLS chain, usually from a private registry or HTTPS-inspecting proxy.
How to Fix It
Confirm which registry host npm is calling:npm config get registry
Check system time and timezone (NTP). If it's wrong, fix it and retry.
Check for proxy settings:npm config get proxy and npm config get https-proxy
Check TLS config:npm config get strict-ssl and npm config get cafile
Run a quick registry check:npm ping
If this only fails on your office/VPN but works on a hotspot, treat it as corporate TLS interception until proven otherwise.
Proper fix:trust the CA that is signing the certificate chain.
If you are behind a corporate TLS proxy, export the corporate root CA and configure npm:npm config set cafile /path/to/corp-ca.pem
In CI, prefer NODE_EXTRA_CA_CERTS=/path/to/corp-ca.pem so Node trusts the internal CA without changing global npm config.
If you control the registry/proxy, ensure it serves the full certificate chain (leaf + intermediates).
Inspect the served chain:openssl s_client -showcerts -connect <host>:443 -servername <host> </dev/null
Temporary diagnostics only:if you must confirm a trust issue, run npm --strict-ssl=false <command> once, then restore validation immediately.
Do not leave strict-ssl=false or NODE_TLS_REJECT_UNAUTHORIZED=0 in CI, shell profiles, or checked-in config. They disable certificate validation and increase MITM risk.
If you changed npm config for a one-off test, revert it immediately:npm config set strict-ssl true and unset NODE_TLS_REJECT_UNAUTHORIZED
Retry with npm --verbose and keep the full output for troubleshooting.
Why It Happens
A corporate proxy/VPN is intercepting HTTPS and presenting a certificate signed by an internal CA that Node does not trust.
Your registry (or proxy registry) is serving an incomplete chain (missing intermediate CA certificates).
System time is incorrect, which can make otherwise valid certificates fail validation.
Node/npm is using a CA trust store that does not include the required issuer certificates.
How to Verify
Run npm ping (same network, same registry) and confirm it succeeds.
Re-run the original command and confirm the TLS error no longer appears.
Manual certificate validation
Confirm the failing host matches your registry:npm config get registry
If you control the registry/proxy, ensure it serves the full certificate chain (leaf + intermediates).
Inspect the served chain:openssl s_client -showcerts -connect <host>:443 -servername <host> </dev/null
If curl works but npm fails, the issue is usually Node's CA trust (fix with NODE_EXTRA_CA_CERTS / cafile).
If you need a short diagnostic retry with SSL disabled, restore validation immediately afterward.
Examples
npm ERR! code DEPTH_ZERO_SELF_SIGNED_CERTHow npm verifies TLS certificates
npm uses Node.js for HTTPS. Certificate validation happens in Node's TLS stack.
The server must provide a valid chain to a trusted root CA, and the certificate must match the hostname.
Proxies that intercept TLS must be trusted by adding their root CA to the client trust store (or configuring cafile).
Prevention Tips
Bake your corporate root CA into CI runner images (or distribute via configuration management).
Use a registry or proxy that serves a complete, valid certificate chain.
Keep Node.js and npm updated so you get current CA bundles and TLS defaults.
Where This Can Be Triggered
github.com/npm/cli/blob/417daa72b09c5129e7390cd12743ef31bf3ddb83/lib/utils/ping.js
This is the registry request path where npm talks to the network. DNS/TLS errors like this code are raised by Node/OS during this request. - GitHub
// used by the ping and doctor commands
const npmFetch = require('npm-registry-fetch')
module.exports = async (flatOptions) => {
const res = await npmFetch('/-/ping', { ...flatOptions, cache: false })
return res.json().catch(() => ({}))
}