| Upstream Unreachable | The host or port in the Service is wrong or unreachable | Try curl from Kong node to upstream: curl http://<host>:<port> |
| Timeouts | Upstream is too slow or hangs | Check Kong logs for timeout messages. Increase read_timeout, connect_timeout |
| DNS Failure | Hostname in Service cannot be resolved | Check Kong container DNS, or use IP to test |
| TCP Refused | Nothing is listening at upstream IP:port | Use telnet <host> <port> or nc to check if port is open |
| SSL Error (for HTTPS upstream) | Invalid certificate or mismatch | Use curl -v https://host and check Kong’s trusted_certificate setting |
| Strip Path issues | Stripping path incorrectly, leading to 404 upstream | Try setting "strip_path=false" or verify upstream path expectations |
| Service Misconfig | Wrong protocol, missing path, or upstream misbehaving | Double check service definition in Admin API or Kong Manager |
Infra Cloud Solutions 