CCNP ENCOR reference
HTTP/REST Response Codes Quick Reference
Fast triage by status-code range plus JSON error-body detail — tested in ENCOR objective 6.6.
Range-based triage
2xx = success. 4xx = client-side error (something about the request — syntax, auth, permission, target). 5xx = server-side error (the problem is on the device/server's end, not the request). Checking the range first tells you which side of the request to investigate before diving into detail.
Don't confuse 401 and 403
401 Unauthorized: no valid authentication presented at all — check credentials/token. 403 Forbidden: authentication was valid, but the account lacks permission for this specific action — check permissions/scope, not credentials.
Check the JSON body too
A well-designed API returns a JSON error body alongside the status code with a specific, actionable message — check both together, not the numeric code alone.
Common codes
| Code | Meaning |
|---|---|
| 200 OK | Successful GET |
| 201 Created | Successful resource creation (POST) |
| 204 No Content | Successful request, no response body (often PUT/PATCH/DELETE) |
| 400 Bad Request | Malformed syntax (e.g. invalid JSON) |
| 401 Unauthorized | Missing/invalid authentication |
| 403 Forbidden | Valid auth, insufficient permission |
| 404 Not Found | Resource/endpoint doesn't exist |
| 500 Internal Server Error | Server/device-side problem |