n8n Troubleshooting Guide

This is the canonical troubleshooting guide for n8n issues. Check here first before debugging.

Note: For detailed learnings and solutions, see N8N_LEARNINGS.md

Quick Troubleshooting Checklist

1. Webhook Not Working?

• [ ] Check webhook URL format in logs
• [ ] Verify credential IDs are correct (not names)
• [ ] Ensure responseMode: lastNode is set
• [ ] Test with cURL first
• [ ] Check environment variables have port 443

2. Telegram Trigger Issues?

• [ ] Environment variables must include :443
• [ ] Only ONE Telegram trigger per bot allowed
• [ ] Check webhook registration with Telegram API
• [ ] Consider using generic webhook instead

3. 502 Bad Gateway?

• [ ] Wait 30 seconds after restart
• [ ] Check logs: docker compose logs --tail 100 n8n
• [ ] Verify n8n is listening on port 5678
• [ ] Check Traefik routing

4. Workflow Stops After Webhook?

• [ ] Check execution logs in UI
• [ ] Verify ALL credential IDs
• [ ] Test each node individually
• [ ] Check field mappings in database nodes

Common Commands

# Quick health check
curl -s -o /dev/null -w "%{http_code}" https://n8n.rbnk.uk/

# View recent errors
docker compose logs --tail 50 n8n | grep -i error

# Check webhook configuration
docker compose exec n8n printenv | grep WEBHOOK

# Restart n8n
docker compose restart n8n

# Full restart (if env changes)
docker compose down && docker compose up -d

Debug Mode

Enable debug logging by adding to docker-compose.yml:

environment:
  - N8N_LOG_LEVEL=debug
  - N8N_LOG_OUTPUT=console
  - DB_LOGGING_ENABLED=true

Getting Help

1. Check N8N_LEARNINGS.md
2. Search n8n community forum
3. Check GitHub issues
4. Enable debug logging
5. Test with minimal workflow