> ## Documentation Index
> Fetch the complete documentation index at: https://plivo.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Zentrunk Hangup Codes

> SIP hangup codes, causes, and troubleshooting for Plivo SIP Trunking

Zentrunk uses four-digit hangup codes to identify call issues. Find these codes in the CDR under Zentrunk → [Logs](https://cx.plivo.com/sip-trunking) in the Plivo console.

***

## Hangup Sources

| Source | Description |
| - | - |
| **Customer** | Hangup initiated by your infrastructure |
| **Carrier** | Hangup initiated by the remote carrier |
| **Zentrunk** | Hangup initiated by Plivo |

***

## Hangup Codes

> [accordion] Normal Hangups (3000-3040)
>
> Normal call terminations - typically no action required.
>
> | Code | Cause | Description | Next Steps |
> | - | - | - | - |
> | 3000 | `normal_hangup` | Normal hangup from carrier | None - call completed normally |
> | 3010 | `normal_hangup` | Normal hangup from user | None - call completed normally |
> | 3020 | `rtp_timeout` | Mid-call media timeout | Check network stability. Verify firewall allows RTP ports (10000-20000 UDP) |
> | 3030 | `insufficient_plivo_credits` | Call ended due to low credits | Add credits. Enable auto-recharge in Console → Billing |
> | 3040 | `abnormal_hangup_due_to_reinvite` | Re-invite rejected | Check for changes in session parameters during call |

> [accordion] Authentication Errors (4000-4060)
>
> Issues with credentials or authorization.
>
> | Code | Cause | Description | Next Steps |
> | - | - | - | - |
> | 4000 | `bad_request` | Malformed SIP request | Check SIP packet format. Don't retry without fixing |
> | 4010 | `unauthorized_by_carrier` | Carrier rejected authentication | Verify carrier credentials are not blacklisted |
> | 4020 | `unauthorized` | Authentication required | Add correct credentials to trunk configuration |
> | 4030 | `insufficient_plivo_credits` | No credits to start call | Add credits to your account |
> | 4040 | `forbidden` | Carrier refused the request | Authorization won't help - check with carrier |
> | 4050 | `blacklisted_for_verification` | Number blacklisted by Zentrunk | Contact Plivo support |
> | 4060 | `forbidden` | PBX authentication failed | Verify credentials on your PBX |

> [accordion] Routing Errors (4070-4120)
>
> Issues finding the destination or route.
>
> | Code | Cause | Description | Next Steps |
> | - | - | - | - |
> | 4070 | `trunk_not_found` | Trunk lookup failed | Verify trunk URI is correct in Console |
> | 4080 | `route_not_found` | No matching trunk URI | Check incoming call route settings |
> | 4090 | `destination_not_found` | No route to destination | Verify destination number. Check carrier availability |
> | 4100 | `prefix_not_supported` | Invalid number prefix | Use correct country prefix for destination |
> | 4110 | `secure_trunking_disabled` | TLS/SRTP used but not enabled | Enable Secure Trunking or use non-secure transport |
> | 4120 | `destination_invalid` | Invalid "To" number format | Use E.164 format: +14155551234 |

> [accordion] Caller ID Errors (4130-4200)
>
> Issues with the caller ID used for the call.
>
> | Code | Cause | Description | Next Steps |
> | - | - | - | - |
> | 4130 | `incorrect_callerid_non_numeric` | Caller ID is not numeric | Use numeric caller ID only |
> | 4140 | `incorrect_callerid_too_short` | Caller ID less than 6 digits | Use full phone number as caller ID |
> | 4180 | `call_rejected_unauthorized` | Authentication failed due to invalid credentials or unauthorized access | Verify your SIP trunk credentials (username/password) or IP ACL configuration. Ensure the trunk's authentication type matches your setup (digest auth vs IP-based) |
> | 4190 | `unknown_caller_id` | Non-Plivo number used as caller ID | Use a Plivo-rented number as caller ID |
> | 4200 | `dno_caller_id` | Caller ID is on Do Not Originate list | Use a different number. This one is inbound-only |

> [accordion] Format & Media Errors (4150-4270)
>
> Issues with SIP message format or media negotiation.
>
> | Code | Cause | Description | Next Steps |
> | - | - | - | - |
> | 4150 | `proxy_authentication_required` | Carrier requires proxy auth | Contact carrier for proxy credentials |
> | 4160 | `request_timeout_carrier` | No response from carrier | Retry. Check carrier availability |
> | 4170 | `request_timeout_customer` | No response from your PBX | Check PBX is online and reachable |
> | 4220 | `unsupported_media_type` | Unsupported codec | Use PCMU, PCMA, or telephone-event codecs |
> | 4230 | `unsupported_uri_scheme` | Unknown request URI | Check SIP URI format |
> | 4270 | `session_interval_too_small` | Session-expires too short | Increase session timer interval |

> [accordion] URI & Availability Errors (4310-4380)
>
> Issues with origination URIs and temporary unavailability.
>
> | Code | Cause | Description | Next Steps |
> | - | - | - | - |
> | 4310 | `uri_not_found` | Origination URI not found | Create origination URI and attach to trunk |
> | 4320 | `uri_invalid` | URI cannot be resolved | Verify domain resolves to valid IP address |
> | 4330 | `temporary_unavailable` | Zentrunk temporarily unavailable | Retry. May indicate CPS limit reached |
> | 4340 | `temporary_unavailable` | Callee temporarily unavailable (carrier) | Retry later. Destination may be offline |
> | 4350 | `temporary_unavailable` | Callee temporarily unavailable (customer) | Check your PBX is online |
> | 4360 | `call_does_not_exist` | Call ID mismatch | Check for duplicate Call-IDs in your system |
> | 4370 | `loop_detected` | Call loop detected | Fix routing to prevent loops |
> | 4380 | `too_many_hops` | Hop limit exceeded | Reduce SIP proxy hops |

> [accordion] Call State Errors (4410-4550)
>
> Issues with call state, busy, or cancellation.
>
> | Code | Cause | Description | Next Steps |
> | - | - | - | - |
> | 4410 | `user_busy` | Destination is busy | Retry later or use voicemail fallback |
> | 4420 | `carrier_cancelled` | Carrier cancelled the call | Check carrier logs for reason |
> | 4430 | `sdp_not_acceptable_here` | SDP not supported | Check SDP format compatibility |
> | 4440 | `request_terminated` | Zentrunk terminated request | Check logs for specific reason |
> | 4500 | `request_pending` | Another request in progress | Wait for current request to complete |
> | 4520 | `security_agreement_required` | Security negotiation needed | Implement required security mechanism |
> | 4540 | `forbidden` | Zentrunk auth failure | Contact Plivo support |
> | 4550 | `user_cancelled` | User cancelled the call | None - caller hung up before answer |

> [accordion] Geo & Number Restrictions (4560-4650)
>
> Calls blocked due to permissions or regulations.
>
> | Code | Cause | Description | Next Steps |
> | - | - | - | - |
> | 4560 | `barred_country` | Country blocked in geo permissions | Enable country in Console → Geo Permissions |
> | 4570 | `barred_number` | Number is barred | Contact support if this is unexpected |
> | 4580 | `invalid_sip_packet` | Malformed SIP packet | Check SIP headers and request format |
> | 4590 | `domestic_anchored_terms_not_met` | India media anchoring violation | For India calls: server must be in India. Don't mix PSTN and WebRTC in conferences |
> | 4650 | — | Number blocked in geo permissions settings (SIP response 403 - Barred Country); calls to the barred country or number group don't go through | If [geo permissions were disabled by Plivo](https://plivo.com/docs/voice/concepts/geo-permissions.md#geo-permissions-disabled-by-plivo), contact support to re-enable them |

> [accordion] SDP & Codec Errors (4610-4640)
>
> Issues with session description protocol or codecs.
>
> | Code | Cause | Description | Next Steps |
> | - | - | - | - |
> | 4610 | `ruri_not_acceptable_here` | Unsupported Request-URI | Check URI format |
> | 4620 | `codec_not_acceptable_here` | Unsupported codec | Use PCMU, PCMA, or telephone-event |
> | 4630 | `sdp_not_acceptable_here_by_carrier` | Carrier rejected SDP | Check SDP compatibility with carrier |
> | 4640 | `sdp_not_acceptable_here_by_user` | Your PBX rejected SDP | Check SDP settings on your PBX |

> [accordion] Server & Capacity Errors (5000-5200)
>
> Server-side issues and capacity limits.
>
> | Code | Cause | Description | Next Steps |
> | - | - | - | - |
> | 5000 | `service_unavailable_no_more_destinations` | No available routes | Retry. Check carrier status |
> | 5010 | `port_limit_reached` | Maximum port capacity reached | Contact support to increase capacity |
> | 5020 | `not_implemented` | Unsupported functionality | Check Zentrunk supported features |
> | 5030 | `not_implemented_at_carrier` | Carrier doesn't support request | Use different request method |
> | 5040 | `not_implemented_at_user` | Your PBX doesn't support request | Update PBX configuration |
> | 5180 | `cps_limit_reached` | Calls per second limit exceeded | Reduce call rate, or ask Buddy in the [console](https://cx.plivo.com/home) to raise your CPS limit |
> | 5190 | `concurrent_call_limit_exceeded` | Account concurrency limit exceeded | Wait for active calls to end, or [increase your concurrency limit](https://plivo.com/docs/sip-trunking/concepts/account-limits.md#increasing-your-limits) |
> | 5200 | `server_timeout` | Timer expired | Retry the request |

> [accordion] Mid-Call & Service Errors (5220-5360)
>
> Errors occurring during active calls.
>
> | Code | Cause | Description | Next Steps |
> | - | - | - | - |
> | 5220 | `service_interrupted_by_customer` | 4xx error during call (customer) | Check your PBX logs |
> | 5230 | `service_interrupted_by_customer` | 5xx/6xx error during call (customer) | Check your PBX logs |
> | 5240 | `service_interrupted_by_nomedia` | Media error during call | Check network connectivity, NAT settings |
> | 5250 | `internal_error` | Backend service issue | Retry. Contact support if persistent |
> | 5260 | `internal_error_routing` | Internal routing issue | Retry. Contact support if persistent |
> | 5270 | `internal_error_media_service` | Media server issue | Retry. Contact support if persistent |
> | 5290 | `internal_error_trunk` | Trunk URI fetch error | Retry. Verify trunk configuration |
> | 5300 | `bad_gateway` | Carrier returned 502 | Check carrier status |
> | 5310 | `service_interrupted_by_carrier_4xx` | 4xx error during call (carrier) | Check carrier logs |
> | 5320 | `service_interrupted_by_carrier_5xx_6xx` | 5xx/6xx error during call (carrier) | Check carrier status |
> | 5330 | `server_timeout` | Carrier timeout | Retry. Check carrier availability |
> | 5340 | `server_timeout` | Your PBX timeout | Check PBX is responsive |
> | 5350 | `service_unavailable_by_carrier` | Carrier temporarily unavailable | Retry later |
> | 5360 | `service_unavailable_by_user` | Your PBX temporarily unavailable | Check PBX status |

> [accordion] Global Failures (6000-6070)
>
> Final failures with no alternatives.
>
> | Code | Cause | Description | Next Steps |
> | - | - | - | - |
> | 6000 | `busy_everywhere` | All destinations busy | Retry later. No voicemail available |
> | 6020 | `does_not_exist_anywhere` | User doesn't exist | Verify the destination number |
> | 6030 | `alloted_timeout` | Answer timeout exceeded | Destination took too long to answer |
> | 6040 | `declined_from_carrier` | Carrier declined the call | Contact carrier for reason |
> | 6070 | `not_acceptable` | Session description not acceptable | Check SDP compatibility |

***

## Getting Help

If issues persist after troubleshooting:

1. Check [Debug Logs](https://plivo.com/docs/sip-trunking/troubleshooting/zentrunk-debug-logs.md) for detailed call information
2. Download SIP PCAP from debug logs for analysis
3. Contact [Plivo Support](https://support.plivo.com) with the Call UUID and hangup code