> ## Documentation Index > Fetch the complete documentation index at: https://trust-link-tsn.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Errors — TSN response and failure codes > Reference the HTTP and JSON-RPC failures currently emitted by TSN services when authentication, validation, routing, or upstream work fails. TSN errors are fail-closed: a route, intent, lease, or upstream provider is not treated as valid when its required evidence is unavailable. ## Node HTTP errors | Status | Meaning in the inspected source | Typical trigger | | ------------- | ---------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- | | `401` / `403` | Authentication or authorization failure | Missing/invalid worker key or a settlement lease owned by another Cranker. | | `404` | Resource does not exist | Unknown intent or TIN operation identifier. | | `409` | State conflict | Duplicate authorization, expired lease, wrong lifecycle state, missing finalized route, or a TCap route being sent through the legacy payout path. | | `422` | Request or signed payload is invalid | Missing required fields, unsupported token, invalid commitment, or malformed route data. | | `503` | Service or route registry is unavailable | Node verifier is not ready or the settlement registry cannot be read safely. | The Node's FastAPI error body is normally an object with a `detail` field. The exact detail text is part of the source behavior for each endpoint and should not be parsed as a stable error code. ## JSON-RPC gateway errors The gateway returns JSON-RPC 2.0 error objects for malformed JSON (`-32700`), invalid JSON-RPC requests (`-32600`), and upstream failure. HTTP status is `400` for malformed/invalid requests and `502` when all upstream providers fail. ## SDK errors `TsnHttpClient` throws `Error("TSN request failed (): ")` for a non-2xx response. Validation helpers in `payment-authorization.ts`, `cross-chain.ts`, and `tins.ts` throw ordinary JavaScript `Error` values with source-defined messages. ## Minimal handling example ```ts theme={null} try { await client.postIntent(request); } catch (error) { const message = error instanceof Error ? error.message : String(error); console.error(message); } ``` TODO: introduce stable machine-readable Node error codes only after the service source defines them. This reference intentionally does not convert current human-readable `detail` strings into invented codes. Source: [`server.py:3500-3640`](https://github.com/Trustlink-Labs/TSN-Protocol/blob/main/tsn-protocol/services/tsn-node/server.py#L3500-L3640), [`server.py:4009-4108`](https://github.com/Trustlink-Labs/TSN-Protocol/blob/main/tsn-protocol/services/tsn-node/server.py#L4009-L4108), [`gateway.mjs:515-579`](https://github.com/Trustlink-Labs/TSN-Protocol/blob/main/tsn-protocol/services/tsn-rpc-gateway/gateway.mjs#L515-L579), [`client.ts:22-62`](https://github.com/Trustlink-Labs/TSN-Protocol/blob/main/tsn-protocol/sdks/tsn-sdk/src/client.ts#L22-L62)