Errors

Error envelope, full code matrix, and per-code troubleshooting.

Error response shape

All non-2xx responses share this envelope:

{
  "error": {
    "code": "past_order_cutoff",
    "message": "The order window for this auction closed at 2026-04-20T12:00:00+09:00.",
    "request_id": "req_8829374",
    "details": {
      "cutoff_at": "2026-04-20T12:00:00+09:00",
      "now": "2026-04-20T12:30:00+09:00"
    }
  }
}

Branch on error.code only. error.message is human-readable English and may evolve. details is structured supplementary info — fields vary per code.

request_id is also returned as the X-Request-Id response header. Include it in any support request.

HTTP → code matrix

HTTP	error.code values
400	validation_error, missing_idempotency_key, missing_max_bid, invalid_cursor, mixed_source_pagination_unsupported
401	missing_api_key, invalid_api_key
403	ip_not_allowed, invalid_status_transition (partner attempting LMN-owned transition)
404	vehicle_not_found, order_not_found, order_vehicle_snapshot_not_found
409	invalid_status_transition, past_order_cutoff, duplicate_order
410	vehicle_unavailable
422	idempotency_key_reused
429	rate_limited
500	internal_error
503	dealer_upstream_unavailable

Per-code troubleshooting

Code	HTTP	Meaning	When	What to do
validation_error	400	Request shape failed validation.	Bad enum, missing field, model without make, ids > 100, from without to.	Inspect error.details.issues[].path. Fix the request; do not retry as-is.
missing_idempotency_key	400	Idempotency-Key header absent on order creation.	POST /v1/orders without header.	Add UUID v4 header, retry.
invalid_cursor	400	Cursor invalid, expired, or sort-mismatched.	Resending a cursor after changing sort=.	Restart pagination from page 1 with the desired sort.
missing_max_bid	400	Auction vehicle requires max_bid_amount_usd.	POST with null/omitted/below-listing bid.	Add max_bid_amount_usd (integer > 0, ≥ listing). Not required for buy-now.
missing_api_key	401	x-api-key header absent.	Any request without header.	Add the header.
invalid_api_key	401	Key not recognized, revoked, or wrong env.	Sandbox key against production URL, or revoked key.	Verify env (sandbox vs production); rotate if compromised.
ip_not_allowed	403	Source IP not in allowlist.	Egress IP missing from per-env allowlist.	Email [e-mail] to add IP. Check egress NAT stability.
invalid_status_transition	403 / 409	Requested transition not permitted.	403 = partner attempted an LMN-owned status (inspection_in_progress, inspection_ready, acquiring, secured, export_processing, in_transit); details.reason: "partner_not_authorized". 409 = sequence violation (e.g., delivered from non-customs, DELETE from non-placed); details.reason: "out_of_sequence". details.current_status set in both cases.	Re-fetch GET /v1/orders/{id} to see current state. Only use partner-permitted transitions: in_transit → customs, customs → delivered.
vehicle_not_found	404	Unknown or unavailable vehicle ID.	Stale ID, wrong-env ID, or a dealer (encar_*) detail page whose upstream advertisement is no longer active / marked SOLD or WAIT.	Refresh the listing; confirm correct base URL. For dealer cars, treat this as no longer available to buy and remove or disable the listing in your UI. Cars you have already ordered are exempt — their detail still resolves from your stored order snapshot, so a purchased vehicle won’t return this error.
order_not_found	404	Unknown order ID for this key.	Wrong env, cross-key ID, or deleted.	Confirm correct base URL; the ID belongs to your account.
order_vehicle_snapshot_not_found	404	Order exists, but no purchased-vehicle snapshot is stored.	GET /v1/orders/{id}/vehicle for a historical order created before snapshot storage.	Use live GET /v1/vehicles/{vehicle_id} only if the listing still exists; otherwise contact LMN for manual recovery.
past_order_cutoff	409	POST after the auction’s cutoff.	auction_date − N min (your integration’s lead time; default 1440 = 24h) already passed.	Inform dealer that the order window is closed.
duplicate_order	409	Active order already exists for this vehicle.	Repeat POST while a prior order is not terminal. details.existing_order_id references it.	Redirect user to existing order page. Do not auto-retry.
idempotency_key_reused	422	Same Idempotency-Key with a different vehicle_id.	Client-library bug reusing keys across logical requests.	Inspect details.original_vehicle_id. Generate a fresh key per new order.
vehicle_unavailable	410	Vehicle no longer available.	Dealer or buy-now listing disappeared before LMN could complete the purchase.	Move order to failed in UI once the order snapshot reflects failure_reason: "vehicle_unavailable"; notify dealer.
rate_limited	429	Per-key rate limit exceeded.	Burst exceeded sliding-window bucket.	Respect Retry-After header; client-side exponential backoff.
internal_error	500	Server-side failure.	Rare; LMN on-call is paged automatically. Body carries only a generic message — no stack traces.	Retry with exponential backoff (3 tries). If persistent, share request_id with support.
mixed_source_pagination_unsupported	400	cursor passed with mixed auction+dealer source.	Trying to paginate beyond page 1 on a query like source=glovis,dealer&cursor=….	Restart pagination per source — issue separate requests with source=glovis and source=dealer. The first page of a mixed query is supported; deeper iteration is not.
dealer_upstream_unavailable	503	A dealer upstream (Encar or Danawa) is unreachable or returned an unexpected response shape.	Transient dealer-source outage, network blip, bot-protection interstitial, or extractor drift. Mixed requests degrade gracefully with X-LMN-Partial-Dealer-Unavailable: <csv> — a comma-separated list of the dealer source names that failed (e.g. encar, danawa, or encar,danawa) — instead of this error; a pure dealer request fails with 503 only when all dealer sources are down (one source down still returns the survivor’s rows + the header).	Retry after a short backoff (5–30s). If persistent (> 5 min for a single ID, > 2 min for list), include request_id and the failing dealer query in a support note — auction requests are unaffected during dealer outages.