> ## 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 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 | 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 | 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 | 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 | 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 | 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 | 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 | 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 | 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 | 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 contact support to increase CPS | | 5190 | `concurrent_call_limit_exceeded` | Too many simultaneous calls | Wait or contact support to increase limit | | 5200 | `server_timeout` | Timer expired | Retry the request | 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 | 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](/sip-trunking/troubleshooting/zentrunk-debug-logs) 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