Resolve common issues with Caddy and Docker setup.

Most Caddy issues relate to certificates, networking, or backend service problems.

Common issues with Caddy include certificate issuance failures, 502 Bad Gateway errors, and configuration problems. This guide helps you diagnose and resolve these issues.

Symptoms:

• HTTPS not working
• Certificate errors in browser
• Caddy logs show certificate errors

Troubleshooting:

• Check DNS propagation: `nslookup your-domain.com`
• Verify ports 80 and 443 are accessible externally
• Check Caddy logs: `docker compose logs caddy`
• Ensure domain points to correct IP
• Wait for DNS propagation (can take up to 48 hours)

Symptoms:

• Browser shows 502 error
• Service appears down

Troubleshooting:

• Check if backend container is running: `docker compose ps`
• Check backend container logs: `docker compose logs service-name`
• Verify service name in Caddyfile matches docker-compose.yml
• Check network connectivity between containers
• Ensure backend service is listening on correct port

Symptoms:

• Container exits immediately
• Container won't start

Troubleshooting:

• Check logs: `docker compose logs service-name`
• Verify configuration: `docker compose config`
• Check port conflicts
• Verify image exists and is accessible
• Check volume permissions

Symptoms:

• Caddy won't start
• Port conflict errors

Troubleshooting:

• Check what's using ports 80 and 443: `sudo netstat -tulpn | grep :80`
• Stop conflicting services
• Use different ports if needed
• Check for other web servers running

Symptoms:

• Caddy won't start
• Configuration errors in logs

Troubleshooting:

• Validate Caddyfile: `docker exec caddy caddy validate –config /etc/caddy/Caddyfile`
• Check for syntax errors
• Verify file paths in volumes
• Check for typos in domain names

• Setting Up Caddy Reverse Proxy with Automatic HTTPS (Docker)

• Caddy Overview
• Caddy Setup

Last updated: 2026-06-19

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