Security & SSL
SSL Certificate Expired
An expired SSL/TLS certificate causes browsers to display security warnings and block users from accessing your website. Modern browsers like Chrome and Firefox show full-page warnings that most users won't bypass. Certificate expiration is one of the most common causes of unexpected website downtime.
Symptoms
- Browser shows "Your connection is not private" error
- ERR_CERT_DATE_INVALID in Chrome
- API clients receiving TLS handshake failures
- Monitoring alerts for HTTPS failures
Common Causes
- Auto-renewal failed (payment issue, DNS validation failure)
- Certificate not replaced before expiration
- Let's Encrypt renewal cron job stopped working
- Wrong certificate installed after renewal
Step-by-Step Troubleshooting
- 1
Check SSL certificate details
Inspect the certificate to confirm expiration date and issuer.
Use SSL Certificate Check → - 2
Verify HTTPS connectivity
Check HTTP headers and response to confirm the server is reachable.
Use HTTP Headers → - 3
Renew the certificate
Renew through your CA dashboard or re-run certbot for Let's Encrypt certificates.
- 4
Verify installation
After renewal, verify the new certificate is properly installed and the chain is complete.
Use SSL Certificate Check →
Recommended Diagnostic Tools
Monitor SSL Expiration
Get alerts days before your SSL certificate expires.