← Glossary / ERR_CERT_AUTHORITY_INVALID

What is ERR_CERT_AUTHORITY_INVALID?

ERR_CERT_AUTHORITY_INVALID is a fatal network error triggered when a browser or HTTP client encounters an SSL/TLS certificate signed by an unrecognized Certificate Authority. In scraping pipelines, this almost always indicates a misconfigured interception proxy — your residential gateway or debugging tool is presenting a self-signed certificate to inspect HTTPS traffic, but your headless browser hasn't been configured to trust it. Left unhandled, it halts the fetch layer before a single byte of HTML is transferred.

Scraping ErrorsSSL/TLSProxy InterceptionHeadless BrowsersNetwork Layer
// 02 — definitions

The chain of
trust breaks.

Why your headless browser refuses to load the page, and how interception proxies accidentally trigger the web's built-in security model.

Ask a DataFlirt engineer →

TL;DR

ERR_CERT_AUTHORITY_INVALID occurs when the certificate chain cannot be verified against the client's root trust store. For scrapers, it's rarely a target site issue. It usually means your MITM proxy is actively decrypting traffic, but you forgot to pass the ignore-certificate-errors flag to Playwright or inject the proxy's custom CA into your container.

01Definition & structure
ERR_CERT_AUTHORITY_INVALID is a Chromium network error indicating that the SSL/TLS certificate presented by a server is signed by an unknown or untrusted entity. During the TLS handshake, the client checks the certificate's issuer against a local list of trusted Certificate Authorities (like DigiCert or Let's Encrypt). If the issuer isn't on the list, the client aborts the connection to prevent potential eavesdropping.
02How interception proxies cause it
To inspect or modify HTTPS traffic, tools like Charles, Mitmproxy, or residential proxy gateways perform a Man-in-the-Middle (MITM) attack on your own traffic. They intercept the connection, generate a fake certificate for the target domain on the fly, and sign it with their own custom CA. Because your headless browser has never seen this custom CA before, it rightly flags the certificate as invalid and throws the error.
03Bypassing in headless browsers
The most common fix in scraping is to disable certificate validation entirely. In Playwright, you pass ignore_https_errors=True when creating a new browser context. In Puppeteer, you launch the browser with the --ignore-certificate-errors argument. This tells the browser to accept any certificate, regardless of who signed it, allowing the intercepted traffic to flow normally.
04Bypassing in HTTP clients
If you are using standard HTTP libraries instead of a browser, the concept is the same. In Python's requests or httpx, you set verify=False. In Node.js axios, you configure an httpsAgent with rejectUnauthorized: false. In cURL, you append the -k or --insecure flag.
05The security trade-off
Disabling TLS validation is standard practice in scraping, but it does mean you are vulnerable to actual MITM attacks on public networks. If you are scraping sensitive data or passing authentication tokens, a better approach is to extract the custom CA certificate from your proxy tool and explicitly add it to your operating system's or container's trusted root store. This maintains strict validation while allowing your specific proxy to operate.
// 03 — the trust model

How TLS validation
fails.

The mathematical and logical checks a client performs during the TLS handshake. When any of these fail, the connection is dropped before the HTTP request is even sent.

Chain verification = V(C) = Root_CA ∈ Trust_Store
If the issuer isn't in the OS or browser trust store, validation fails immediately. RFC 5280 — PKI Certificate Profile
Playwright bypass = context = browser.new_context(ignore_https_errors=True)
Disables all certificate validation for the browser session. Playwright API
Requests bypass = response = requests.get(url, verify=False)
Python's equivalent. Generates an InsecureRequestWarning by default. urllib3 / requests
// 04 — proxy interception trace

A failed MITM
handshake.

What happens when a scraper routes traffic through an SSL-inspecting proxy without trusting the proxy's root certificate.

PlaywrightMITM ProxyTLS 1.3
edge.dataflirt.io — live
CAPTURED
// outbound connection
client.hello: target="example.com" proxy="10.0.0.5:8080"
proxy.intercept: generating dynamic cert for "example.com"

// inbound TLS
server.hello: cipher="TLS_AES_256_GCM_SHA384"
server.certificate: issuer="O=Mitmproxy, CN=mitmproxy"

// validation phase
cert.verify: checking issuer against local root store
cert.issuer_found: false

// fatal error
tls.alert: unknown_ca (48)
connection.status: closed
playwright.error: net::ERR_CERT_AUTHORITY_INVALID at https://example.com
// 05 — root causes

Where the invalid
certs come from.

Ranked by frequency across DataFlirt's debugging logs. Proxy misconfiguration accounts for the vast majority of these errors in production scraping environments.

SAMPLE SIZE ·  ·  ·  ·    1.2M errors
WINDOW ·  ·  ·  ·  ·  ·   30d trailing
UPDATED ·  ·  ·  ·  ·  ·  2026-05-19
01

SSL-inspecting proxy (MITM)

89% of errors · Charles, Mitmproxy, or residential gateways
02

Expired target certificate

6% of errors · Target site forgot to renew Let's Encrypt
03

Missing intermediate CA

3% of errors · Target server misconfigured chain
04

Corporate firewall interception

1.5% of errors · Local network security appliances
05

Self-signed target cert

0.5% of errors · Usually staging or internal target environments
// 06 — DataFlirt's approach

Trust the proxy,

ignore the noise.

In a controlled scraping environment, strict TLS validation is often an unnecessary hurdle. Because we route traffic through our own proprietary proxy gateways to manage IP rotation and header injection, we intentionally intercept and rewrite TLS handshakes. DataFlirt's managed browser fleet is pre-configured to trust our internal CA, ensuring seamless interception without triggering authority errors, while still validating the upstream target's certificate at the edge.

tls.validation.config

Edge proxy TLS termination settings for a managed pipeline.

edge.interception active
edge.ca_issuer DataFlirt Internal Root G3
client.trust_store injected
upstream.verify strict
upstream.expired drop connection
pipeline.status routing nominally

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// 07 — FAQ

Common
questions.

About TLS validation, proxy interception, security trade-offs, and how to bypass certificate errors in production scrapers.

Ask us directly →
What exactly does ERR_CERT_AUTHORITY_INVALID mean? +
It means the HTTP client or browser received an SSL certificate, looked at the "Issuer" field, and couldn't find that issuer in its local list of trusted Certificate Authorities (the root store). Because it can't verify who signed the certificate, it assumes the connection is compromised and aborts the handshake.
Is it safe to ignore certificate errors in a scraper? +
Generally, yes. Ignoring certificate errors exposes you to Man-in-the-Middle (MITM) attacks, but in a scraping context, you are usually MITMing yourself via a proxy to inspect traffic or route requests. Since you aren't transmitting sensitive personal data or passwords to the target, the security risk of a compromised TLS session is minimal.
Why does the site work in my normal Chrome but fail in Puppeteer? +
Your normal Chrome installation uses your operating system's trust store, which likely has your corporate firewall or proxy's custom CA installed. Puppeteer downloads its own isolated Chromium binary, which does not automatically inherit those OS-level trusted roots, causing it to reject the proxy's certificate.
How do I fix this in Python requests? +
Pass verify=False in your request call: requests.get(url, verify=False). This will bypass validation but print an InsecureRequestWarning to your console. To suppress the warning, use urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning) before making the request.
How does DataFlirt handle proxy certificates? +
We terminate TLS at our edge gateways to inject headers and manage rotation. Our managed browsers are injected with our internal CA at startup, so the scraper sees a valid certificate chain. Our edge nodes then handle the actual upstream validation against the target site, dropping connections if the target's real certificate is invalid.
Can a target site use this error to detect bots? +
Not directly, because the error happens locally on your machine before the HTTP request is ever sent to the target. However, if you bypass the error, advanced anti-bot systems can sometimes detect the presence of an interception proxy by analyzing the modified TLS fingerprint (JA3/JA4) that your proxy presents to the server.
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hello@dataflirt.com  ·  Bengaluru  ·  IST  ·  typical reply < 4h
// 08 — keep reading

Related glossary terms

DevTools

Mitmproxy

The standard tool for intercepting and inspecting HTTPS traffic, which often triggers this error.

Read →
Network Layer

SSL Certificate Validation

The underlying cryptographic process that fails when an invalid authority is encountered.

Read →
Scraping Errors

Proxy Connection Error

Other common network-layer failures that occur when routing traffic through proxy pools.

Read →
Network Layer

TLS Handshake

The protocol negotiation phase where certificate validation occurs before HTTP data flows.

Read →