> ## Documentation Index > Fetch the complete documentation index at: https://docs.ravan.ai/llms.txt > Use this file to discover all available pages before exploring further. # Error codes > Understand call failure errors, SIP status codes, Twirp wrappers, and the recommended next step for each failure. # Error codes Use this page to understand why a call failed and what action to take next. Call failures usually come from the telephony layer, so the most useful value is the **SIP status code** shown in the call details. Twirp and HTTP codes may appear in technical details. These describe how the LiveKit API returned the failure. The SIP status explains the actual phone-call outcome. *** ## How to read call errors When an outbound call fails, the call detail page may show an error like: ```text theme={null} 480: Temporarily Unavailable ``` Technical details may include a Twirp wrapper like: ```text theme={null} TwirpError(code=resource_exhausted, status=429, metadata={ "sip_status_code": "480", "sip_status": "Temporarily Unavailable" }) ``` In this example: | Field | Meaning | | ------------------------- | ------------------------------------------------------ | | `480` | SIP status code. This is the main call failure reason. | | `Temporarily Unavailable` | SIP status text shown by the telephony provider. | | `resource_exhausted` | Twirp error code returned by the LiveKit API. | | `429` | HTTP status for the Twirp response. | *** ## Call failure codes | SIP code | Status | What it means | Recommended action | Agni tag | | -------: | ----------------------- | ------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------- | ------------------------------ | | `480` | Temporarily Unavailable | The callee could not receive the call right now. The phone may be off, unreachable, out of coverage, or temporarily unable to accept calls. | Try again later. If it repeats, verify the number and carrier reachability. | `call_status:User Unavailable` | | `486` | Busy Here | The callee is busy, already on another call, or the line rejected the call because it is occupied. | Try again later or call another number for the same contact. | `call_status:User Busy` | | `408` | Request Timeout | The call timed out before the network or callee responded. | Try again. If it repeats, confirm the number and check telephony provider routing. | Not tagged automatically | | `403` | Forbidden | The call was blocked by permission, routing, geo-permission, or provider policy. | Check phone number permissions, SIP trunk settings, and allowed destination countries. | Not tagged automatically | | `404` | Not Found | The number or route could not be found by the carrier or telephony provider. | Confirm the phone number is valid and in E.164 format. | Not tagged automatically | | `487` | Request Terminated | The call attempt was cancelled before it connected. | Retry the call. Check whether the campaign or user cancelled the attempt. | Not tagged automatically | | `500` | Server Error | A provider or telephony service returned an internal error. | Retry after a short delay. Contact support if the issue continues. | Not tagged automatically | | `503` | Service Unavailable | The carrier or telephony service was temporarily unavailable. | Retry later. Check provider status if many calls fail at once. | Not tagged automatically | | `603` | Decline | The callee or carrier declined the call. | Try again later or use another contact method. | Not tagged automatically | *** ## Twirp error wrapper Some call failures are returned through a Twirp error wrapper. For call troubleshooting, use the SIP metadata first. | Twirp code | HTTP status | What it usually means in call failures | | -------------------- | ----------: | ----------------------------------------------------------------------------------------------------------------------------- | | `resource_exhausted` | `429` | LiveKit returned the SIP failure through a resource-exhausted response. Check `sip_status_code` and `sip_status` in metadata. | | `unauthenticated` | `401` | The LiveKit API credentials were missing or invalid. Check `LIVEKIT_API_KEY` and `LIVEKIT_API_SECRET`. | | `permission_denied` | `403` | The credentials are valid, but the request is not allowed. Check permissions and SIP trunk access. | | `not_found` | `404` | The requested room, trunk, participant, or API route was not found. | | `unavailable` | `503` | The LiveKit API or a dependent service was temporarily unavailable. Retry later. | | `internal` | `500` | An internal service error occurred. Retry and contact support if it continues. | Agni currently adds automatic call-status tags for `480 Temporarily Unavailable` and `486 Busy Here`. Other errors may still appear in technical details, but they are not mapped to custom call-status tags yet. *** ## What to include when contacting support When you contact support about a failed call, include: * The call ID or session ID * The phone number or contact involved * The visible error code and status * The Twirp code and HTTP status, if shown * The timestamp of the failed call This helps support identify whether the issue came from the number, carrier, SIP trunk, LiveKit API, or Agni configuration.