Lingua-e
← Errors
Python

SSLCertVerificationError: What It Means and How to Fix It

Error reference

SSLCertVerificationError

Language

Python

Severity

High

When it happens

ssl.SSLCertVerificationError is raised when Python's SSL layer cannot verify the server's TLS certificate.

Potential fixes

On macOS, run the 'Install Certificates.command' script in your Python installation directory. Update your CA bundle with certifi. If you control the server, renew the expired certificate. Never disable SSL verification in production code.

Related errors

ConnectionErrorConnectionRefusedErrorTimeoutError

Deep dive

ssl.SSLCertVerificationError is raised when Python's SSL layer cannot verify the server's TLS certificate. This can mean the certificate is expired, self-signed, issued by an untrusted authority, or the hostname does not match the certificate.

Why it happens

  • •The server's SSL certificate has expired.
  • •A self-signed certificate is used without adding it to the trusted store.
  • •The system's CA bundle is outdated or missing (common on macOS after Python install).
  • •A corporate proxy performs SSL inspection and presents its own certificate.

Potential fixes

On macOS, run the 'Install Certificates.command' script in your Python installation directory. Update your CA bundle with certifi. If you control the server, renew the expired certificate. Never disable SSL verification in production code.

Examples

Python

Code that triggers the error

import urllib.request
urllib.request.urlopen("https://expired.badssl.com/")

Error output

ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: certificate has expired (_ssl.c:1007)

Fixed code

import requests

# Production: keep verification enabled
response = requests.get("https://api.example.com", timeout=10)

# Development only: disable verification (never in production)
# response = requests.get("https://...", verify=False)

Practice in English

How would you explain a SSLCertVerificationError to a fellow dev? Choose the right phrase:

"I hit an error...

Ready to practice your English at work?

Lingua-e has interactive exercises built around real developer conversations: standups, code reviews, retrospectives, and more. Practice until it comes naturally.

Try Lingua-e for free