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Troubleshooting

Troubleshooting SSL/TLS Certificate Problems

Diagnose certificate errors, configuration issues, and common TLS failures.

CertOne1 min read

Certificate problems can arise at several points in deployment. This guide covers common failures and how to diagnose them.

1. Common certificate errors​

1. Expired certificate​

Symptom: the browser reports that the certificate has expired.

Resolution:

  • Check the certificate validity period
  • Renew the certificate
  • Configure automatic renewal

2. Incomplete certificate chain​

Symptom: some browsers report that the certificate is not trusted.

Resolution:

  • Use the full-chain certificate file
  • Configure the server to send the intermediate chain

3. Hostname mismatch​

Symptom: the browser reports a hostname mismatch.

Resolution:

  • Make sure the certificate covers the requested hostname
  • Deploy the correct certificate

2. Configuration problems​

1. Incorrect certificate path​

Check the configured certificate file paths.

2. File permissions​

Make sure the server has the necessary read permissions.

3. Server configuration​

Check the web server's TLS configuration.

3. Diagnostic steps​

1. Inspect the certificate​

Use OpenSSL to inspect certificate details.

2. Review server logs​

Check the NGINX or Apache error logs.

3. Use testing tools​

Test the TLS configuration with tools such as SSL Labs.

Conclusion​

A systematic diagnostic process helps locate and resolve certificate problems quickly.