unexpected status 404 Not Found: Model not found gpt-5.4

Resolved 💬 27 comments Opened Apr 21, 2026 by theblackboxinyourhead Closed Apr 21, 2026

💡 Likely answer: A maintainer (github-actions[bot], contributor) responded on this thread — see the highlighted reply below.

What version of Codex CLI is running?

latest

What subscription do you have?

pro

Which model were you using?

5.4

What platform is your computer?

macos

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

latest

What issue are you seeing?

after the numerous 403s and experiencing high demand errors today, now its a 404

What steps can reproduce the bug?

send a request on 5.4

What is the expected behavior?

_No response_

Additional information

_No response_

View original on GitHub ↗

27 Comments

Higor-Matos · 3 months ago

+1 Mac Os

AriaShishegaran · 3 months ago

mengdehong · 3 months ago

+1 Archlinux （CLI and VScode plugin）

unexpected status 404 Not Found: Model not found gpt-5.4, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: 9ef8d480db368ea2-SJC, request id: e16df69a-0679-4cb2-x

github-actions[bot] contributor · 3 months ago

Potential duplicates detected. Please review them and close your issue if it is a duplicate.

#18762
#18682
#18688
#18686

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chullino · 3 months ago

+1 MacOS vscode codex

jimmycarp966 · 3 months ago

+1 windows

AriaShishegaran · 3 months ago

Also getting this:


Falling back from WebSockets to HTTPS transport. unexpected status 404 Not Found:
  Model not found gpt-5.4-t

What is the "t"?

playhuck · 3 months ago

+1 Ubuntu

? Falling back from WebSockets to HTTPS transport. unexpected status
  404 Not Found: Model not found gpt-5.4-t

? Conversation interrupted - tell the model what to do differently.
Something went wrong? Hit `/feedback` to report the issue.

seanbajuice · 3 months ago

+1 windows

raederhans · 3 months ago

same issue from Windows, seems its the problem of server? I switched to 5.3 codex and works as for now

josheee1117 · 3 months ago

+1windows

AbelHuang7 · 3 months ago

chanhuaxiang · 3 months ago

Neurolancer81 · 3 months ago

+1
■ unexpected status 404 Not Found: Model not found gpt-5.4, url:
https://chatgpt.com/backend-api/codex/responses,

AriaShishegaran · 3 months ago

new model coming? :D a/b test gone wrong? :D

chullino · 3 months ago

run run codex, Claude's got to make it to town

papaya0481 · 3 months ago

+1 ubuntu

PeterDraex · 3 months ago

new model coming? :D a/b test gone wrong? :D

i've been refreshing https://openai.com/news/ but nothing yet 😅

chullino · 3 months ago

me solved :)

starsingchow · 3 months ago

+1 macos

physics91 · 3 months ago

solved me

AriaShishegaran · 3 months ago

> new model coming? :D a/b test gone wrong? :D i've been refreshing https://openai.com/news/ but nothing yet 😅

well, it's gonna be any day now. I'm actually looking fw to it, see if they have made any meaningful design improvements or it is still gonna "capsule" and "card" its way out of any UI it is given to design. Much more reliable on backend tasks so far.

Higor-Matos · 3 months ago

fix

goblindespiser · 3 months ago

+1 windows

waldennia · 3 months ago

seems fixed

hyunbenny · 3 months ago

+1 windows

jfhfhgfhf · 1 month ago

+1 windows