ModAPISTROUBLESHOOTING · ERROR FAQ
Kling API Error Codes: Python Troubleshooting Guide
Most "Kling API not working" reports resolve into one of a dozen codes across two phases: setup (auth, parameters, balance) and generation (content review, queue, upstream). The other half of the problem is client-side habit — code that branches on HTTP status alone misses the codes that matter. This page is a field guide to both, in Python, ending with a worked error-branch example against Kling 3.0 on ModAPIS. Pair it with the Veo error guide for task-model triage and the polling guide for hung tasks.
Setup-phase errors: auth, parameters, balance
- 401 invalid/missing key: the key isn't being sent — check the Authorization header format and the environment variable actually loaded in your process.
- 403: key valid but lacking access to the model tier; confirm the model name string exactly ("kling-3.0", not "kling3" or "kling-3").
- 422: unsupported duration/resolution/audio combination for that tier — the body says which field; fix the parameter, don't retry.
- 402 insufficient credits: balance exhausted mid-day; top up or catch and pause your queue instead of retry-looping.
Generation-phase errors: review, queue, upstream
- Content review failure: task reaches FAILURE with a filter code — rewrite the prompt; not retryable as-is.
- Queue full / busy: upstream saturated; retryable with backoff, minutes not seconds.
- Upstream switch mid-task: a redundant channel takes over; usually invisible, occasionally surfaces as a slower task — not an error, don't kill it.
- Timeout/hung: exceeds your wall-clock budget — see the polling guide's thresholds.
Read the body code, not just the HTTP status
The single highest-value habit: after every response, parse the JSON body and branch on the error code field. Two failures with the same HTTP 200 can mean "task created" and "task rejected"; two different statuses can carry the same actionable code. Shape to expect on ModAPIS: {"error": {"code": "...", "retryable": true/false, "action": "..."}} — the action string is the instruction ("backoff_and_retry", "rewrite_prompt", "check_credentials"), written to be routed on directly.
import os, requests
API = "https://api.modapis.com/v1"
H = {"Authorization": f"Bearer {os.environ['MODAPIS_API_KEY']}"}
task = requests.post(f"{API}/videos", headers=H, json={
"model": "kling-3.0",
"prompt": "a corgi running down a rain-soaked Tokyo street",
}).json()
err = task.get("error")
if err:
if err["code"].startswith("CONTENT"):
queue_rewrite(task) # not retryable
elif err["retryable"]:
backoff_and_resubmit(task) # idempotency key goes here
else:
alert(f"{err['code']}: {err['action']}")Webhook-driven completion checks
Polling works, but webhooks are the robust completion signal for Kling: register a callback URL at submit, and the terminal state (completed or failed, with the error object if failed) is pushed to you. Webhooks on ModAPIS are free in every tier. Treat the webhook as authoritative and polling as fallback — the inverse arrangement tends to produce duplicate-generation bugs when a webhook is delayed and a poll-driven retry fires first.
The same code, one handler
The error contract above is identical across the catalog — the handler you write for Kling 3.0 handles video, image, and music endpoints unchanged, and failed tasks are not charged. Working examples for Kling 3.0 (curl / Python / JS) are on the model page; the quickstart gets a key and first request running in five minutes.