ERR_SSL_OCSP_INVALID_RESPONSE

• OCSP response expired — nextUpdate passed
• CA OCSP responder returns stale data
• Cache invalidation delay on CDN
• Wrong OCSP signer cert
• Clock skew on server (> 1 hour)

1. Check system clock: timedatectl status
2. Force OCSP refresh: reload nginx, wait 5 min
3. Temporarily disable verify: ssl_stapling_verify off;
4. Update chain: ssl_trusted_certificate with fresh CA chain
5. CA outage — valid within an hour

Check SSL Certificate →

• ERR_SSL_PROTOCOL_ERROR
• NET::ERR_CERT_AUTHORITY_INVALID
• SSL Handshake Failed
• All SSL errors

The ERR_SSL_OCSP_INVALID_RESPONSE error in Chrome indicates a failure in the Online Certificate Status Protocol (OCSP) response verification, often due to a misconfigured server or network issues. To resolve this, ensure your server is correctly configured to provide OCSP responses, check for firewall or proxy interference, and verify the SSL certificate's validity using tools like openssl or online SSL checkers.

The ERR_SSL_OCSP_INVALID_RESPONSE error occurs when a browser fails to validate an SSL certificate's revocation status through OCSP. This protocol allows browsers to check if a certificate has been revoked by the Certificate Authority (CA) without having to download the entire Certificate Revocation List (CRL). When this validation fails, users are presented with this error message.

Common causes include:

• Server Misconfiguration: The web server may not be correctly set up to respond to OCSP requests.
• Network Issues: Firewalls or proxies may block OCSP requests or responses, causing validation failures.
• Expired or Invalid Certificates: If the SSL certificate itself is expired or not properly issued, OCSP responses may be invalid.

To diagnose the issue, you can use the following command to check the OCSP response directly:

openssl ocsp -issuer issuer_cert.pem -cert user_cert.pem -url http://ocsp.example.com

This command checks the OCSP response for a given user certificate against its issuer. If the response is valid, you will see confirmation; if it fails, you may need to troubleshoot further.

To effectively resolve the ERR_SSL_OCSP_INVALID_RESPONSE error, follow these steps:

1. Check Your SSL Certificate: Use SSL checker tools like SSL Shopper to confirm that your SSL certificate is valid and properly configured.
2. Verify OCSP Settings: Ensure your web server is set up to handle OCSP requests. For Apache, you can add the following lines to your configuration:

SSLUseStapling on
SSLStaplingCache "shmcb:/var/run/ocsp-status(128000)"

These directives enable OCSP stapling and specify a cache location for OCSP responses.

1. Check Network Configuration: Make sure that firewalls or proxies are not blocking OCSP traffic. You may need to allow outbound traffic on port 80 (HTTP) and port 443 (HTTPS).
2. Test OCSP Response: Use the curl command to test the OCSP response directly:

curl -v http://ocsp.example.com

This will show you the response headers and any potential issues. Look for the HTTP/1.1 200 OK status to ensure the OCSP responder is reachable.

1. Consult Your Certificate Authority: If issues persist, contact your CA for assistance. They can provide insights into potential revocation issues or misconfigurations.

By systematically following these steps, you can effectively troubleshoot and resolve the ERR_SSL_OCSP_INVALID_RESPONSE error, ensuring secure connections for your users.