GPT 5.5 has a 404
What issue are you seeing?
Unable to use 5.5 in Codex even though I see & select the model in the picker.
Error in Mac app:
unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a08222f6a834f242-MAA, request id: 54446a05-6a0d-49e6-8e2e-28aee034bb33
Error running remote compact task: unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses/compact, cf-ray: a08214d91db6ff18-MAA, request id: 48e90786-b13c-45d5-a452-dde67d6e4394
Error in CLI:
⚠ Falling back from WebSockets to HTTPS transport. unexpected status 404 Not Found: Model not found gpt-5.5-codex-1p-exp-p-0604-811f2f-ev3-text-control
unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a0823e0aeef01ae3-MAA, request id: b0f817ea-359d-4e8e-8294-6473b68ce2b0
What steps can reproduce the bug?
Turn on the model to 5.5 in Codex (CLI or mac app) - any reasoning, speed is fine - and I see these errors.
Works perfect with 5.4, mini..
Local Codex model cache still lists gpt-5.5 as available/selectable
I also reset Codex auth and local models cache, and the same 404 persists in both CLI and macOS app.
What is the expected behavior?
_No response_
Additional information
Codex macOS app 26.602.40724 (build 3593)
My ChatGPT plan is Plus (India)
gpt-5.5 works in ChatGPT
gpt-5.4 works in Codex
22 Comments
Potential duplicates detected. Please review them and close your issue if it is a duplicate.
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Closing since this is a duplicate of https://github.com/openai/codex/issues/26892
I had the same question, how to fix it?
Same question here
When will it be fixed?
Error running remote compact task: unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses/compact, cf-ray: a086831eaff80e0c-BOM, request id: 37e707b6-2921-467e-8c16-7a6bea3c4b83
Same here:
unexpected status 404 Not Found: Model not found gpt-5.5, url:
https://chatgpt.com/backend-api/codex/responses, cf-ray: a08753cb38f1dcd5-CGY, request id:
b7493e67-24ac-4da2-b79a-2392c471d415
Got the same:
unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a0880acaef0ace4f-SIN, request id: bc43ac5d-ce69-4142-ab7d-4cfbb6a1bf4e
Sam please help, unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a08883baed653e40-BOM, request id: f04673f9-3e06-418f-951a-12e47106f964
Hi everyone! Sorry, we are looking into this. Will report back here shortly.
Samer here on codex CLI
Reconnecting... 3/5 (19s • esc to interrupt)
└ Unexpected status 404 Not Found: Model not found gpt-5.5-codex-1p-exp-p-0604-811f2f-ev3-text-control
Thanks for your patience. The backend issue causing
gpt-5.5requests to return404 Model not foundis now resolved.Please try again. If it still fails, share a fresh request ID and timestamp.
same here today unexpected status 404 Not Found: Unknown error, url: https://chatgpt.com/backend-api/codex/responses, cf-ray......
Unfortunately I started reciving the same error message today, just from a couple of minutes ago:
unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a100d35999f6562f-ARN, request id: 6c22f935-99dc-4f33-a9d8-58dd04721ea4
Same error here, Error running remote compact task: unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a1015fab3cacea1b-ICN, request id: 9983d18a-b89b-4732-bc7a-f1d511764661
我也遇到同样的问题了，甚至新开对话，仍然无法连接。 unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a10269dcb84bdd7b-MAD, request id: 7d02081e-ae03-425f-aed3-562b76e0b4e9
i have same issue
unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a101f161492eb115-JED, request id: f864b9f6-13bc-4b31-9a6c-b4859da60e77
unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a101fd999c480dc8-JED, request id: ee5239e9-224f-475e-abf1-3351f8ea0848
unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a102073d9ff2881e-JED, request id: f5c5faf6-3e0b-4986-aa99-a795733c8ea7
unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a102591228bc0430-JED, request id: a53913fb-26be-452d-8045-25f462579d94
unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a102710b0ad5f536-JED, request id: 7e427a54-1641-45e0-84a1-894a7931641a
unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a102a2239c2588e3-JED, request id: 0294d6a7-48aa-4ab3-9510-22559a2219a2
I had the same question, how to fix it?
unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a102ec02cbd7f7d7-LAX, request id: 34a530d4-9fa9-4eb6-a3e1-81fa81211d4c
It was working just 10 minutes ago, but then the same error suddenly occurred.
It might be because I updated the app. with Codex Mac Version 26.616.71553 • Released Jun 23, 2026
what i can do to solve this problem ?
unexpected status 404 Not Found: Model not found gpt-5.5, url: https://chatgpt.com/backend-api/codex/responses, cf-ray: a107d2a13cf40df8-HKG, request id: 0360ac20-4d7a-4d13-9ad3-cd203fa45cd7
this work with me now, when i change the model to gpt-5.4-mini and back to gpt-5.5 .