How to fix npm ERR! code 128 npm ERR! fatal: unable to access 'https://github.com/': SSL certificate problem in npm

npmINTERMEDIATEMEDIUMUpdated Dec 5, 2025· 239 views

This error occurs when npm can't verify the SSL certificate when cloning a Git dependency. Usually caused by corporate proxies, self-signed certificates, or outdated CA certificates.

Quick fix

Fixes npm ERR! code 128 npm ERR! fatal: unable to access 'https://github.com/': SSL certificate problem

# Test direct git access
git clone https://github.com/user/repo.git

# Check what certificate is being served
openssl s_client -connect github.com:443 -servername github.com
  1. Identify the certificate source
  2. Add corporate CA certificate (recommended)
  3. Configure Git to use the certificate
  4. Configure npm proxy (if behind proxy)
npm — error
# Test direct git access
git clone https://github.com/user/repo.git
# Check what certificate is being served
openssl s_client -connect github.com:443 -servername github.com
npm ERR! code 128
npm ERR! fatal: unable to access 'https://github.com/': SSL certificate problem

What this error means

When npm tries to clone a Git dependency over HTTPS, it verifies the server's SSL certificate. This error means the certificate couldn't be verified—either because a corporate proxy is intercepting the connection, the certificate is self-signed, or the system's certificate store is outdated. This is extremely common in corporate environments where security proxies inspect HTTPS traffic by injecting their own certificates. It can also occur with private Git servers that use self-signed certificates. The error often shows specific details like "unable to get local issuer certificate" or "certificate verify failed."

Typical symptoms

  • npm install fails with 'SSL certificate problem'
  • Error code 128 from git
  • Works on home network but fails at office
  • Only affects HTTPS Git URLs, not SSH
  • May show 'unable to get local issuer certificate'

Common causes

  1. Corporate proxy intercepting HTTPS traffic with its own certificate
  2. Self-signed certificate on private Git server
  3. Outdated CA certificate bundle on system
  4. Missing root certificate authority in trust store
  5. VPN or proxy not properly configured

How to fix "npm ERR! code 128 npm ERR! fatal: unable to access 'https://github.com/': SSL certificate problem"

1Identify the certificate source

First, determine if this is a corporate proxy issue:

bash
# Test direct git access
git clone https://github.com/user/repo.git

# Check what certificate is being served
openssl s_client -connect github.com:443 -servername github.com

If the certificate issuer looks like your company (not DigiCert or similar), it's likely a corporate proxy.

2Add corporate CA certificate (recommended)

If your company uses SSL inspection, get the CA certificate from IT and configure Node.js to trust it:

bash
# Set environment variable to add extra CA certificates
export NODE_EXTRA_CA_CERTS=/path/to/corporate-ca.pem

# Make it permanent in your shell profile
echo 'export NODE_EXTRA_CA_CERTS=/path/to/corporate-ca.pem' >> ~/.bashrc

For Windows:

cmd
set NODE_EXTRA_CA_CERTS=C:\path\to\corporate-ca.pem
3Configure Git to use the certificate

Tell Git to trust the certificate:

bash
# For specific repository
git config http.sslCAInfo /path/to/corporate-ca.pem

# Or globally
git config --global http.sslCAInfo /path/to/corporate-ca.pem

On Windows, use the native certificate store:

bash
git config --global http.sslBackend schannel
4Configure npm proxy (if behind proxy)

If you're behind a corporate proxy:

bash
npm config set proxy http://proxy.company.com:8080
npm config set https-proxy http://proxy.company.com:8080
5Clear cache and retry

After configuring certificates:

bash
rm -rf node_modules package-lock.json
npm cache clean --force
npm install

Advanced notes

Never Disable SSL in Production: Disabling SSL verification (npm config set strict-ssl false or git config http.sslVerify false) opens you to man-in-the-middle attacks. Only use these temporarily to diagnose issues, never in CI/CD or production.

NODE_EXTRA_CA_CERTS vs cafile: NODE_EXTRA_CA_CERTS adds to the existing trusted certificates, while npm config set cafile replaces them. Always prefer NODE_EXTRA_CA_CERTS.

Getting Corporate Certificates:
1. Ask your IT department for the CA certificate in PEM format
2. Export from browser: visit any HTTPS site, view certificate, export the root CA
3. On Windows, export from certmgr.msc

Certificate Format: The certificate must be in PEM format (starts with -----BEGIN CERTIFICATE-----). Convert from other formats:

bash
openssl x509 -inform der -in certificate.cer -out certificate.pem

Frequently asked questions

What does "npm ERR! code 128 npm ERR! fatal: unable to access 'https://github.com" mean?
When npm tries to clone a Git dependency over HTTPS, it verifies the server's SSL certificate. This error means the certificate couldn't be verified—either because a corporate proxy is intercepting the connection, the certificate is self-signed, or the system's certificate store is outdated. This is extremely common in corporate environments where security proxies inspect HTTPS traffic by injecting their own certificates.
How do I fix "npm ERR! code 128 npm ERR! fatal: unable to access 'https://github.com"?
This error occurs when npm can't verify the SSL certificate when cloning a Git dependency. Usually caused by corporate proxies, self-signed certificates, or outdated CA certificates.
What causes "npm ERR! code 128 npm ERR! fatal: unable to access 'https://github.com"?
Corporate proxy intercepting HTTPS traffic with its own certificate Self-signed certificate on private Git server Outdated CA certificate bundle on system
Is the "npm ERR! code 128 npm ERR! fatal: unable to access 'https://github.com" error serious?
It is a medium-severity error — more of a blocker than a risk. The steps above resolve it.

Official resources & further reading