SSL_ERROR_NO_RENEGOTIATION

Enterno.io Editorial Team

By Anatoly Oshmanovsky · Updated Apr 18, 2026

Key idea:

SSL_ERROR_NO_RENEGOTIATION — Firefox tried to renegotiate the TLS session (e.g. for client cert auth on a specific path), but the server refused. Renegotiation is deprecated for security reasons (CVE-2009-3555). nginx with ssl_verify_client on per-location requires renegotiation on Firefox, while Chrome uses an HTTP/2-compatible approach.

Below: causes, fixes, FAQ.

Try it now — free →

Common Causes

nginx per-location ssl_verify_client on
Apache SSLVerifyClient require in
TLS 1.3 without post-handshake auth support
Server disabled renegotiation for security
LB/proxy does not support renegotiation

Step-by-Step Fix

Move client auth to a separate subdomain
Use TLS 1.3 post-handshake auth (nginx 1.19+)
Alternative: pre-configured client cert in TLS handshake
Enterno SSL for renegotiation support check
HTTP/2 requires a separate connection for client auth

Check SSL Certificate →

Related SSL Errors

CertificateExpiry, issuer, domains (SAN)

ChainIntermediate and root CA validation

TLS ProtocolTLS version and cipher suite

VulnerabilitiesHeartbleed, POODLE, weak ciphers

Why teams trust us

TLS 1.3

supported

Full

CA chain check

<2s

result

30/14/7

days-to-expiry alerts

How it works

Enter domain

TLS chain verified

Expiry date & vulnerabilities

What Does the SSL Check Cover?

SSL/TLS is the encryption protocol that protects data between the browser and server. Our tool analyzes the certificate, chain of trust, TLS version, and knownvulnerabilities.

Certificate Details

Issuer, validity period, signature algorithm, covered domains (SAN), and validation type (DV/OV/EV).

Chain of Trust

Full chain verification: from leaf certificate through intermediates to root CA.

TLS Analysis

Protocol version (TLS 1.2/1.3), cipher suites, Perfect Forward Secrecy (PFS) support.

Expiry Alerts

Set up a monitor — get Telegram and email alerts 30/14/7 days before expiration.

DV vs OV vs EV Certificates

DV (Domain Validation)

Confirms domain ownership only
Issued in minutes automatically
Free via Let's Encrypt
Suitable for most websites
Most common certificate type

OV / EV

Organization (OV) or Extended Validation (EV)
Issued in 1-5 business days
Costs $50 to $500/year
For finance, e-commerce, government sites
Increases user trust

Who uses this

DevOps

SSL certificate monitoring

Security

TLS config audit

SEO

HTTPS as ranking factor

E-commerce

customer trust

Common Mistakes

❌

Expired certificateBrowsers block sites with expired SSL. Set up auto-renewal or monitoring.

❌

Incomplete certificate chainWithout intermediate CA, some browsers and bots cannot verify the certificate.

❌

Mixed content on HTTPS siteHTTP resources on an HTTPS page — the browser lock icon disappears, reducing trust.

❌

Using TLS 1.0/1.1Legacy TLS versions have known vulnerabilities. Use TLS 1.2+ or 1.3.

❌

Domain mismatch in certificateThe certificate must cover all site domains, including www and subdomains.

Best Practices

✓

Set up auto-renewalLet's Encrypt + certbot with cron — certificate renews automatically every 60-90 days.

✓

Enable HSTSStrict-Transport-Security header forces browsers to always use HTTPS.

✓

Use TLS 1.3TLS 1.3 is faster (1-RTT handshake) and safer — legacy ciphers removed.

✓

Monitor expiration datesCreate a monitor on Enterno.io — get notified well before expiration.

✓

Verify chain after renewalAfter certificate renewal, confirm that intermediate certificates are installed.

Get more with a free account

SSL certificate monitoring, check history and alerts 30 days before expiry.

Learn more

Research

TLS 1.3 Adoption 2026: Growth Pace

Errors

Frequently Asked Questions

Is renegotiation deprecated?

Secure renegotiation (RFC 5746) ok. Insecure renegotiation — CVE-2009-3555. TLS 1.3 removed renegotiation entirely and replaced it with post-handshake auth.

HTTP/2 + client auth?

HTTP/2 does not support renegotiation → separate subdomain for client auth is the modern approach.

Firefox workaround?

Disable TLS 1.3: security.tls.version.max=3 in about:config. NOT recommended.

OpenSSL config?

<code>ssl_protocols TLSv1.2 TLSv1.3;</code> + apply client auth on TLS 1.3 only.