python network_error ai_generated true

aiohttp.client_exceptions.ClientConnectorCertificateError: Cannot connect to host api.example.com:443 ssl:True [SSLCertVerificationError: (1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1006)')]

ID: python/aiohttp-cannot-connect-to-host-ssl

Also available as: JSON · Markdown · 中文
80%Fix Rate
87%Confidence
0Evidence
2024-02-14First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.8+ active — — —
3.9+ active — — —
3.10+ active — — —
3.11+ active — — —
3.12+ active — — —

Root Cause

The client cannot find the CA bundle to verify the server certificate, often on macOS Python.org builds or in containers missing ca-certificates.

generic

中文

客户端找不到用于验证服务器证书的 CA 证书包，常见于 macOS 官方 Python 构建或缺少 ca-certificates 的容器中。

Workarounds

  1. 95% success 
    import ssl, certifi, aiohttp
ctx = ssl.create_default_context(cafile=certifi.where())
conn = aiohttp.TCPConnector(ssl=ctx)
async with aiohttp.ClientSession(connector=conn) as s:
    ...
  2. 90% success 
    # macOS
/Applications/Python\ 3.12/Install\ Certificates.command

Dead Ends

Common approaches that don't work:

  1. 40% fail

    Disables TLS verification entirely, exposing the app to MITM; often blocked by security policy.

  2. 90% fail

    The issue is the system trust store, not the aiohttp package.