Security & SSL

SSL Certificate Chain Incomplete

An incomplete SSL certificate chain occurs when intermediate certificates are not properly installed on the server. While some browsers can fetch missing intermediates, others (especially mobile browsers and API clients) will fail with untrusted certificate errors.

Symptoms

  • SSL works in some browsers but fails in others
  • Mobile browsers showing security warnings
  • API clients failing with certificate verification errors
  • SSL testing tools showing chain issues

Common Causes

  • Intermediate certificate not installed on the server
  • Wrong order of certificates in the chain file
  • Using a self-signed certificate in production
  • CA changed their intermediate certificate

Step-by-Step Troubleshooting

  1. 1

    Analyze SSL chain

    Check the full certificate chain for missing intermediates.

    Use SSL Certificate Check →
  2. 2

    Download correct intermediates

    Get the proper intermediate certificates from your CA's documentation.

  3. 3

    Reinstall with full chain

    Install the certificate with the complete chain: server cert → intermediate(s) → root.

  4. 4

    Verify the fix

    Re-test SSL to confirm the full chain is served correctly.

    Use SSL Certificate Check →

Recommended Diagnostic Tools

SSL Certificate Check

Monitor SSL Health

Continuously verify SSL certificate chain integrity.

Related Problems

Frequently Asked Questions