unexpected status 404 Not Found solve for now

What version of Codex CLI is running?

latest

What subscription do you have?

Plus

Which model were you using?

gpt-5.6-luna medium Codex

What platform is your computer?

Windows

What terminal emulator and version are you using (if applicable)?

wsl

Codex doctor report

{
  "schemaVersion": 1,
  "generatedAt": "1788450180s since unix epoch",
  "overallStatus": "ok",
  "codexVersion": "0.153.0",
  "checks": {
    "app_server.status": {
      "id": "app_server.status",
      "category": "app-server",
      "status": "ok",
      "summary": "background server is not running",
      "details": {
        "control socket": "/home/bruno/.codex/app-server-control/app-server-control.sock",
        "daemon state dir": "/home/bruno/.codex/app-server-daemon",
        "mode": "ephemeral",
        "pid file": "/home/bruno/.codex/app-server-daemon/app-server.pid (missing)",
        "settings": "/home/bruno/.codex/app-server-daemon/settings.json (missing)",
        "status": "not running",
        "update-loop pid file": "/home/bruno/.codex/app-server-daemon/app-server-updater.pid (missing)"
      },
      "remediation": null,
      "durationMs": 0
    },
    "auth.credentials": {
      "id": "auth.credentials",
      "category": "auth",
      "status": "ok",
      "summary": "auth is configured",
      "details": {
        "auth file": "/home/bruno/.codex/auth.json",
        "auth storage mode": "File",
        "stored API key": "false",
        "stored ChatGPT tokens": "true",
        "stored agent identity": "false",
        "stored auth mode": "chatgpt"
      },
      "remediation": null,
      "durationMs": 0
    },
    "config.load": {
      "id": "config.load",
      "category": "config",
      "status": "ok",
      "summary": "config loaded",
      "details": {
        "CODEX_HOME": "/home/bruno/.codex",
        "config.toml": "/home/bruno/.codex/config.toml",
        "config.toml parse": "ok",
        "cwd": "/home/bruno",
        "enabled feature flags": "shell_tool, view_image, sleep_tool, unified_exec, unified_exec_zsh_fork, shell_snapshot, content_item_kinds, code_mode_host, terminal_resize_reflow, sqlite, hooks, enable_request_compression, unbounded_connection_retries, multi_agent, apps, tool_search_always_defer_mcp_tools, tool_suggest, plugins, in_app_browser, in_app_chat, in_app_dictation, in_app_local_automation, in_app_updates, browser_use, browser_use_full_cdp_access, browser_use_external, computer_use, remote_plugin, plugin_sharing, image_generation, resize_all_images, item_ids, skill_mcp_dependency_install, skill_search, mentions_v2, steer, guardian_approval, goals, collaboration_modes, tool_call_mcp_elicitation, auth_elicitation, personality, fast_mode, tui_app_server, remote_compaction_v2, compaction_image_budget, workspace_dependencies",
        "feature flag overrides": "none",
        "feature flags enabled": "47",
        "log dir": "/home/bruno/.codex/log",
        "mcp servers": "0",
        "model": "gpt-5.6-luna",
        "model provider": "openai",
        "sqlite home": "/home/bruno/.codex"
      },
      "remediation": null,
      "durationMs": 0
    },
    "git.environment": {
      "id": "git.environment",
      "category": "git",
      "status": "ok",
      "summary": "git version 2.53.0",
      "details": {
        "PATH git #1": "/usr/bin/git",
        "PATH git #2": "/bin/git",
        "PATH git entries": "2",
        "git build options": "git version 2.53.0; cpu: x86_64; no commit associated with this build; sizeof-long: 8; sizeof-size_t: 8; shell-path: /bin/sh; rust: disabled; gettext: enabled; libcurl: 8.18.0; zlib: 1.3.1; SHA-1: SHA1_DC; SHA-256: SHA256_BLK; default-ref-format: files; default-hash: sha1",
        "git exec path": "/usr/lib/git-core",
        "git version": "git version 2.53.0",
        "repo detected": "false",
        "selected git": "/usr/bin/git"
      },
      "remediation": null,
      "durationMs": 141
    },
    "installation": {
      "id": "installation",
      "category": "install",
      "status": "ok",
      "summary": "installation looks consistent",
      "details": {
        "PATH codex #1": "/home/bruno/.local/bin/codex",
        "current executable": "/home/bruno/.codex/packages/standalone/releases/0.153.0-x86_64-unknown-linux-musl/bin/codex",
        "install context": "standalone (unix, package /home/bruno/.codex/packages/standalone/releases/0.153.0-x86_64-unknown-linux-musl, bin /home/bruno/.codex/packages/standalone/releases/0.153.0-x86_64-unknown-linux-musl/bin, resources /home/bruno/.codex/packages/standalone/releases/0.153.0-x86_64-unknown-linux-musl/codex-resources, path /home/bruno/.codex/packages/standalone/releases/0.153.0-x86_64-unknown-linux-musl/codex-path)",
        "managed by Vite+": "false",
        "managed by bun": "false",
        "managed by npm": "false",
        "managed by pnpm": "false",
        "managed package root": "not set"
      },
      "remediation": null,
      "durationMs": 46
    },
    "mcp.config": {
      "id": "mcp.config",
      "category": "mcp",
      "status": "ok",
      "summary": "no MCP servers configured",
      "details": {},
      "remediation": null,
      "durationMs": 0
    },
    "network.env": {
      "id": "network.env",
      "category": "network",
      "status": "ok",
      "summary": "network-related environment looks readable",
      "details": {
        "managed proxy": "not configured",
        "proxy env vars": "none",
        "respect system proxy": "disabled"
      },
      "remediation": null,
      "durationMs": 0
    },
    "network.provider_reachability": {
      "id": "network.provider_reachability",
      "category": "reachability",
      "status": "ok",
      "summary": "active provider endpoints are reachable over HTTP",
      "details": {
        "ChatGPT inference URL": "https://chatgpt.com/backend-api/<redacted> reachable (HTTP 405)",
        "reachability mode": "ChatGPT auth"
      },
      "remediation": null,
      "durationMs": 231
    },
    "network.websocket_reachability": {
      "id": "network.websocket_reachability",
      "category": "websocket",
      "status": "ok",
      "summary": "Responses WebSocket handshake succeeded",
      "details": {
        "DNS": "2 IPv4, 2 IPv6, first IPv4",
        "auth mode": "chatgpt",
        "connect timeout": "15000 ms",
        "endpoint": "wss://chatgpt.com/backend-api/<redacted>",
        "handshake result": "HTTP 101 Switching Protocols",
        "model provider": "openai",
        "provider name": "OpenAI",
        "proxy env vars": "none",
        "reasoning header": "false",
        "server model present": "false",
        "supports websockets": "true",
        "wire API": "responses"
      },
      "remediation": null,
      "durationMs": 1163
    },
    "runtime.provenance": {
      "id": "runtime.provenance",
      "category": "runtime",
      "status": "ok",
      "summary": "running standalone on linux-x86_64",
      "details": {
        "commit": "unknown",
        "current executable": "/home/bruno/.codex/packages/standalone/releases/0.153.0-x86_64-unknown-linux-musl/bin/codex",
        "install method": "standalone (unix, package /home/bruno/.codex/packages/standalone/releases/0.153.0-x86_64-unknown-linux-musl, bin /home/bruno/.codex/packages/standalone/releases/0.153.0-x86_64-unknown-linux-musl/bin, resources /home/bruno/.codex/packages/standalone/releases/0.153.0-x86_64-unknown-linux-musl/codex-resources, path /home/bruno/.codex/packages/standalone/releases/0.153.0-x86_64-unknown-linux-musl/codex-path)",
        "platform": "linux-x86_64",
        "version": "0.153.0"
      },
      "remediation": null,
      "durationMs": 0
    },
    "runtime.search": {
      "id": "runtime.search",
      "category": "search",
      "status": "ok",
      "summary": "search is OK (bundled)",
      "details": {
        "search command": "/home/bruno/.codex/packages/standalone/releases/0.153.0-x86_64-unknown-linux-musl/codex-path/rg",
        "search command readiness": "file exists",
        "search provider": "bundled"
      },
      "remediation": null,
      "durationMs": 0
    },
    "sandbox.helpers": {
      "id": "sandbox.helpers",
      "category": "sandbox",
      "status": "ok",
      "summary": "sandbox configuration is readable",
      "details": {
        "approval policy": "OnRequest",
        "codex-linux-sandbox helper": "/home/bruno/.codex/tmp/arg0/codex-arg0Jei8Uk/codex-linux-sandbox",
        "execve wrapper helper": "/home/bruno/.codex/tmp/arg0/codex-arg0Jei8Uk/codex-execve-wrapper",
        "filesystem sandbox": "restricted",
        "network sandbox": "restricted"
      },
      "remediation": null,
      "durationMs": 0
    },
    "security.endpoint": {
      "id": "security.endpoint",
      "category": "security",
      "status": "ok",
      "summary": "endpoint protection is not inspected on this platform",
      "details": {
        "endpoint products": "not inspected on this platform"
      },
      "remediation": null,
      "durationMs": 0
    },
    "state.paths": {
      "id": "state.paths",
      "category": "state",
      "status": "ok",
      "summary": "state paths and databases are inspectable",
      "details": {
        "CODEX_HOME": "/home/bruno/.codex (dir)",
        "active rollout files": "4 files, 200200093 total bytes, 50050023 average bytes",
        "archived rollout files": "0 files, 0 total bytes, 0 average bytes",
        "goals DB": "/home/bruno/.codex/goals_1.sqlite (file)",
        "goals DB integrity": "ok",
        "log DB": "/home/bruno/.codex/logs_2.sqlite (file)",
        "log DB integrity": "ok",
        "log dir": "/home/bruno/.codex/log (missing)",
        "memories DB": "/home/bruno/.codex/memories_1.sqlite (file)",
        "memories DB integrity": "ok",
        "queue DB": "/home/bruno/.codex/queue_1.sqlite (file)",
        "queue DB integrity": "ok",
        "sqlite home": "/home/bruno/.codex (dir)",
        "standalone release cache": "5 entries in /home/bruno/.codex/packages/standalone/releases",
        "state DB": "/home/bruno/.codex/state_5.sqlite (file)",
        "state DB integrity": "ok",
        "thread history DB": "/home/bruno/.codex/thread_history_1.sqlite (file)",
        "thread history DB integrity": "ok"
      },
      "remediation": null,
      "durationMs": 2765
    },
    "state.rollout_db_parity": {
      "id": "state.rollout_db_parity",
      "category": "threads",
      "status": "ok",
      "summary": "rollout files and state DB thread inventory agree",
      "details": {
        "default model provider": "openai",
        "rollout DB active files": "4",
        "rollout DB active rows": "4",
        "rollout DB archive mismatches": "0",
        "rollout DB archived files": "0",
        "rollout DB archived rows": "0",
        "rollout DB duplicate DB paths": "0",
        "rollout DB duplicate rollout thread ids": "0",
        "rollout DB malformed file names": "0",
        "rollout DB missing active rows": "0",
        "rollout DB missing archived rows": "0",
        "rollout DB model providers": "openai=4",
        "rollout DB rows": "4",
        "rollout DB scan cap reached": "false",
        "rollout DB scan errors": "0",
        "rollout DB sources": "cli=4",
        "rollout DB stale rows": "0"
      },
      "remediation": null,
      "durationMs": 112
    },
    "system.disk": {
      "id": "system.disk",
      "category": "disk",
      "status": "ok",
      "summary": "sufficient free disk space (944.8 GiB)",
      "details": {
        "CODEX_HOME available": "944.8 GiB",
        "failure threshold": "1.0 GiB",
        "warning threshold": "5.0 GiB",
        "worktree available": "944.8 GiB"
      },
      "remediation": null,
      "durationMs": 0
    },
    "system.environment": {
      "id": "system.environment",
      "category": "system",
      "status": "ok",
      "summary": "OS language C",
      "details": {
        "EDITOR": "not set",
        "LANG": "C.UTF-8",
        "VISUAL": "not set",
        "os": "Ubuntu 26.4.0 (resolute) [64-bit]",
        "os language": "C",
        "os type": "Ubuntu",
        "os version": "26.4.0"
      },
      "remediation": null,
      "durationMs": 32
    },
    "terminal.env": {
      "id": "terminal.env",
      "category": "terminal",
      "status": "ok",
      "summary": "terminal metadata was detected",
      "details": {
        "DISPLAY": "present",
        "WAYLAND_DISPLAY": "present",
        "WSL_DISTRO_NAME": "present",
        "WSL_INTEROP": "present",
        "WT_SESSION": "present",
        "color output": "enabled",
        "effective locale": "C.UTF-8",
        "stderr is terminal": "true",
        "stdin is terminal": "true",
        "stdout is terminal": "true",
        "terminal": "Windows Terminal",
        "terminal size": "108x30"
      },
      "remediation": null,
      "durationMs": 0
    },
    "terminal.title": {
      "id": "terminal.title",
      "category": "title",
      "status": "ok",
      "summary": "terminal title default",
      "details": {
        "terminal title activity": "true",
        "terminal title items": "activity, project-name",
        "terminal title project source": "cwd",
        "terminal title project value": "bruno",
        "terminal title source": "default"
      },
      "remediation": null,
      "durationMs": 0
    },
    "updates.status": {
      "id": "updates.status",
      "category": "updates",
      "status": "ok",
      "summary": "update configuration is locally consistent",
      "details": {
        "cached latest version": "0.153.0",
        "check for update on startup": "true",
        "last checked at": "2026-09-03T06:24:10.591992769Z",
        "latest version": "0.153.0",
        "latest version status": "current version is not older",
        "update action": "standalone installer",
        "version cache": "/home/bruno/.codex/version.json"
      },
      "remediation": null,
      "durationMs": 465
    }
  }
}

What issue are you seeing?

unexpected status 404 Not Found:
wss://chatgpt.com/backend-api/codex/responses

Then the HTTPS fallback also failed:

unexpected status 404 Not Found:
https://chatgpt.com/backend-api/codex/responses

Selecting Luna manually with /model restored the session immediately.

The issue appeared only during the automatic model transition.
Feedback was recorded, but no diagnostic logs were attached.

What steps can reproduce the bug?

Uploaded thread: 01a066ce-7736-7102-a744-f3fe67603058 Or mention your thread ID 01a066ce-7736-7102-a744-f3fe67603058

What is the expected behavior?

⚠ Falling back from WebSockets to HTTPS transport. unexpected status 404 Not Found: Unknown error, url:
wss://chatgpt.com/backend-api/codex/responses, cf-ray: a355b2cceeedea73-FCO

■ unexpected status 404 Not Found: Unknown error, url: https://chatgpt.com/backend-api/codex/responses, cf-ray:
a355b302b938ea58-FCO

Additional information

No response

The issue names no source file or test. Start by reproducing the 404 with Codex CLI 0.153.0 under Windows WSL, using the supplied doctor report and ChatGPT backend reachability details, then trace the request path that returns the status. Done means the same setup no longer reports the unexpected 404 and the behavior has regression coverage.