{"record":{"id":"37abf7c44a33285e","repo":"BerriAI/litellm","slug":"the-response-from-start-url-is-missing-required","errorCode":null,"errorMessage":"The response from {start_url} is missing required field(s): {', '.join(missing_fields)}. The proxy version may not match this CLI; upgrade whichever is older.","messagePattern":"The response from (.+?) is missing required field\\(s\\): (.+?)\\. The proxy version may not match this CLI; upgrade whichever is older\\.","errorType":"exception","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"litellm/proxy/client/cli/commands/auth.py","lineNumber":457,"sourceCode":"        raise ValueError(\n            f\"Starting CLI login failed: HTTP {response.status_code} from {start_url}\"\n            + (f\": {detail}\" if detail else \"\")\n        )\n\n    try:\n        data: Final[CliSsoStartData] = response.json()\n    except ValueError:\n        content_type: Final = response.headers.get(\"content-type\", \"unknown\")\n        raise ValueError(\n            f\"The proxy returned a non-JSON response from {start_url} (content-type: {content_type}). \"\n            \"A proxy, load balancer, or auth gateway in front of LiteLLM may be intercepting the request. \"\n            f\"Response starts with: {response.text[:200]!r}\"\n        )\n\n    required_fields: Final[tuple[str, ...]] = (\"login_id\", \"poll_secret\", \"user_code\")\n    missing_fields: Final = tuple(field for field in required_fields if not isinstance(data.get(field), str))\n    if missing_fields:\n        raise ValueError(\n            f\"The response from {start_url} is missing required field(s): {', '.join(missing_fields)}. \"\n            \"The proxy version may not match this CLI; upgrade whichever is older.\"\n        )\n    return data\n\n\ndef _get_cli_sso_poll_headers(poll_secret: str) -> dict[str, str]:\n    return {\"x-litellm-cli-poll-secret\": poll_secret}\n\n\ndef _poll_for_authentication(base_url: str, key_id: str, poll_secret: str) -> CliAuthResult | None:\n    \"\"\"\n    Poll the server for authentication completion and handle team selection.\n\n    Returns:\n        Dictionary with authentication data if successful, None otherwise\n    \"\"\"\n    poll_url: Final = f\"{base_url}/sso/cli/poll/{key_id}\"","sourceCodeStart":439,"sourceCodeEnd":475,"githubUrl":"https://github.com/BerriAI/litellm/blob/77b7c6c40c0c5aa5fbcb1d6a1825ac39ca8829b8/litellm/proxy/client/cli/commands/auth.py#L439-L475","documentation":"Raised in the CLI SSO flow after a 2xx response when the parsed JSON object is missing one or more required fields of CliSsoStartData (e.g. the login/verification URLs). The missing field names are listed and the message suggests a version mismatch: the CLI is talking to an older/newer proxy whose /sso/cli/start contract differs; upgrade whichever side is older.","triggerScenarios":"Thrown at litellm/proxy/client/cli/commands/auth.py:457 when the library encounters an invalid state.","commonSituations":"The proxy's login response lacked fields the CLI expects (version mismatch).","solutions":["Upgrade whichever is older: the proxy or the CLI, so their login flows match."],"exampleFix":"pip install -U litellm and upgrade the proxy deployment.","handlingStrategy":"validation","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"77b7c6c40c0c5aa5fbcb1d6a1825ac39ca8829b8","analyzedAt":"2026-08-18T11:44:31.656Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}