How to fix HTTPS probe failed: x509: certificate signed by unknown authority in Kubernetes

What this error means

HTTPS liveness/readiness probes fail due to invalid or self-signed certificates. Probes cannot verify the server certificate, causing health checks to fail. Kubernetes uses strict certificate validation by default and will reject unverified certificates.

Typical symptoms

• Probe events: "HTTPS probe failed: x509: certificate signed by unknown authority"
• Pod keeps restarting due to failed HTTPS probes
• HTTP probes work but HTTPS probes fail
• curl to pod shows certificate validation error
• Pod cannot serve HTTPS traffic
• Self-signed certificates rejected by probes
• Intermittent probe failures if certificate expires

Common causes

1. Application using self-signed certificate not trusted by kubelet
2. Certificate expired or invalid
3. Wrong certificate installed on pod
4. Certificate does not match service domain name
5. CA certificate not in system trust store
6. Probe configured with wrong TLS settings
7. Certificate revoked or blacklisted

How to fix "HTTPS probe failed: x509: certificate signed by unknown authority"

Advanced notes

Related errors

• Failed to connect to server: connection refused (HTTP/2)

  How to fix "HTTP/2 connection refused" error in Kubernetes

  HIGH

• missing request for cpu in container

  How to fix "missing request for cpu in container" in Kubernetes HPA

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• error: invalid configuration

  How to fix "error: invalid configuration" in Kubernetes

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Official resources & further reading

• 📚Kubernetes Official Documentation
• 📖
  Kubernetes API Reference(Official Docs)
• 📖
  Kubernetes Tasks: Run Applications(Official Docs)
• 💬
  Stack Overflow: Kubernetes https probe certificate error(Stack Overflow)
• 🐙
  Kubernetes GitHub Issues(GitHub)