{
  "id": "communication/sip-406-not-acceptable",
  "signature": "SIP/2.0 406 Not Acceptable",
  "signature_zh": "SIP/2.0 406 不可接受",
  "regex": "SIP/2\\.0 406 Not Acceptable",
  "domain": "communication",
  "category": "protocol_error",
  "subcategory": null,
  "root_cause": "The SIP server cannot generate a response that matches the Accept header sent by the client.",
  "root_cause_type": "generic",
  "root_cause_zh": "SIP服务器无法生成符合客户端发送的Accept标头的响应。",
  "versions": [
    {
      "version": "Asterisk 20.5.0",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "FreeSWITCH 1.10.11",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "Kamailio 5.7.0",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "Disable all SIP security checks in the server",
      "why_fails": "The 406 is about content negotiation, not security; disabling security may create vulnerabilities.",
      "fail_rate": 0.7,
      "condition": "",
      "sources": []
    },
    {
      "action": "Ignore Accept headers entirely in client code",
      "why_fails": "The server may still reject requests if Accept headers are missing or malformed; proper negotiation is required.",
      "fail_rate": 0.6,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Modify the SIP INVITE to include an Accept header with supported media types. Example: 'Accept: application/sdp' in the request. In Asterisk: set sip.conf globalaccept=application/sdp",
      "success_rate": 0.8,
      "how": "Modify the SIP INVITE to include an Accept header with supported media types. Example: 'Accept: application/sdp' in the request. In Asterisk: set sip.conf globalaccept=application/sdp",
      "condition": "",
      "sources": []
    },
    {
      "action": "Ensure the SIP server supports the requested media format. For example, in FreeSWITCH, check the codec list: 'show codec' and add missing codecs to the dialplan.",
      "success_rate": 0.85,
      "how": "Ensure the SIP server supports the requested media format. For example, in FreeSWITCH, check the codec list: 'show codec' and add missing codecs to the dialplan.",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [
    "Modify the SIP INVITE to include an Accept header with supported media types. Example: 'Accept: application/sdp' in the request. In Asterisk: set sip.conf globalaccept=application/sdp",
    "Ensure the SIP server supports the requested media format. For example, in FreeSWITCH, check the codec list: 'show codec' and add missing codecs to the dialplan."
  ],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": "https://datatracker.ietf.org/doc/html/rfc3261#section-21.4.7",
  "official_doc_section": null,
  "error_code": "406",
  "verification_tier": "ai_generated",
  "confidence": 0.82,
  "fix_success_rate": 0.75,
  "resolvable": "true",
  "first_seen": "2024-01-22",
  "last_confirmed": "2024-06-01",
  "last_updated": "2024-06-01",
  "evidence_count": 1,
  "tags": [],
  "locale": "en",
  "aliases": []
}