> ## Documentation Index > Fetch the complete documentation index at: https://docs.driver.dev/llms.txt > Use this file to discover all available pages before exploring further. # Errors > Every status the API returns, what it means, and whether retrying helps. Errors are JSON with an `error` message; the create call's `503` also has a `code`. A `429` or `502` from the edge in front of the API may not be JSON, so read the status first and parse the body defensively. ```json theme={"dark"} { "error": "Insufficient balance" } ``` ```json theme={"dark"} { "error": "No eligible node found", "code": "browser_capacity_unavailable" } ``` Common bodies: `401` `Unauthorized: Missing or invalid Authorization header` or `Unauthorized: Invalid token`; `402` `Insufficient balance`; `403` `Session limit reached` (concurrency) or `Extensions API is not enabled for this account`; `400` names the field, for example `Unsupported timezone "Europe/Berlin" for country US.` or `windowSize must be WIDTHxHEIGHT with width 320–16384 and height 200–16384`. Unknown fields in a body are a `400` too. ## Status codes The dedicated-IP codes here (`invalid_spec`, `dedicated_ip_not_owned`, `no_dedicated_ip`, `dedicated_ip_unhealthy`) come back when `proxyUrl` names a `dedicated://` address. The dashboard resolves the address before the create call, so Launch browser never returns them. | Status | Meaning | Retry? | | ------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------- | | `400` | Invalid or incompatible options, an unknown field on create, a missing `sessionId`, an update to an ended session, or a malformed dedicated IP spec (`code: invalid_spec`). The message names the problem. | No. Fix the request. | | `401` | Missing or invalid API key. | No. Check `Authorization: Bearer …`. | | `402` | The workspace is out of credits. | No. Add credits in the dashboard. | | `403` | Concurrent-browser limit (`plan.concurrent_browsers` on `GET /v1/account/billing`; `starting` sessions count, a stop frees the slot as soon as it returns), a feature (extensions) the account isn't enabled for, or a [dedicated IP](/docs/options/proxies#dedicated-ips) the workspace doesn't own (`code: dedicated_ip_not_owned`). | Only after a session ends. Never in a loop. | | `404` | Session, extension, pool, lease or account not found: unknown id, or one belonging to another workspace. On create, no dedicated IP matches the spec (`code: no_dedicated_ip`). Deleting an unknown profile isn't a 404; it answers `{ "success": true }`. | No. | | `409` | Browser pools only: a duplicate pool name, a size over the account's warm-browser cap, an acquire that found nothing ready within `waitMs` (`No browser is currently ready in this pool`), an acquire on a paused pool, or a delete with active leases. See [Browser pools](/docs/sessions/pools#errors). | Only the acquire one, as for `503`: back off, cap, then fall back to a plain create or report. | | `429` | Too many requests, from the edge; the API itself doesn't rate-limit today. | Yes: a few attempts, a couple of seconds apart and growing. | | `502` | The edge couldn't reach the API. Not JSON. | Once, after a couple of seconds. | | `500` | Something failed on Driver's side. | Once. | | `503` | No browser capacity. Carries `Retry-After: 2` and `"code": "browser_capacity_unavailable"`. Or the session service is unavailable. With `code: dedicated_ip_unhealthy`, the dedicated IP failed its last health check: use another address. | Yes: back off with jitter, cap the attempts, then tell the user. | | `504` | A machine was selected but Chrome wasn't reachable before the startup deadline (20 s, up to 3 min on some machines). | Once. | ## Guidance for agents and automations * Never loop on `402` or `403`. Surface the message; a person has to act. * `503` is transient: start at the `Retry-After` of 2 seconds, grow with jitter, cap the attempts, then report. Retry `504` and `500` once. * After a `504` nothing is running; no stop call needed. * `DELETE` on an ended session still returns `{ "success": true }`. A `404` means the id was never a session of this workspace. ## Framework-side failures Some failures show up in the framework, not as an HTTP status: | Symptom | Likely cause | | ------------------------------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `Target closed` / `Browser closed` mid-run | The session reached its `duration`, or was stopped from the dashboard. Check `GET /v1/browser/session`. | | Connection refused on `cdpUrl` | The session isn't `active` yet or has ended. | | The site shows a challenge or block page | Framework fingerprint or automation tactics. Switch to [Patchright](/docs/frameworks/patchright) and remove CDP hooks; then escalate: `type: "hosted_stealth"`, `"hosted_privacy"`, `captchaSolver: true`, and finally a person through the [live view](/docs/sessions/live-view). | | `net::ERR_SOCKS_CONNECTION_FAILED` on every navigation | The session's egress isn't reachable. Stop it and create another, in a different country if it persists; report it if it keeps happening. |