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Codex Is Down

OpenAI's Codex desktop app (version 26.611.61753) is failing for some Pro subscribers with repeated 'unexpected status 404 Not Found' errors from the chatgpt.com backend, interrupting long-running sessions. A user on a GPT-5.4 xhigh session reported the error three times in a row, while a separate GPT-5.5 xhigh session remained unaffected, and the issue persisted after retries. The user suggests more resilient retry logic with exponential backoff to prevent mid-session failures.

read2 min views4 publishedSep 3, 2026
Codex Is Down
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appIssues related to the Codex desktop appIssues related to the Codex desktop app

bugSomething isn't workingSomething isn't working

connectivityIssues involving networking or endpoint connectivity problems (disconnections)Issues involving networking or endpoint connectivity problems (disconnections)

sessionIssues involving session (thread) management, resuming, forking, naming, archivingIssues involving session (thread) management, resuming, forking, naming, archiving

Description #

EDIT: To everyone here, the solution was actually reasonably simple, just follow these instructions.

What version of the Codex App are you using (From “About Codex” dialog)?

26.611.61753

What subscription do you have?

Pro x20

What platform is your computer?

Darwin 25.3.0 arm64 arm

What issue are you seeing?

Repeatedly encountering in my GPT 5.4 xhigh session:

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

I can send a message and get an update back, but then when the agent would think and continue I encountered this error 3 times in a row.

I have another session running with GPT 5.5 xhigh and it seems to be unaffected.

What steps can reproduce the bug?

I have a long running session going, it's had many compactions and plenty of steering. I've also been spinning up sub-agents for smaller tasks where this session is acting as an orchestrator. It failed shortly after steering it to spin up a sub-agent, not sure if that's related.

Session stopped with this error, it retried 5/5 times and gave up. This did not occur immediately after compaction, but it was shortly there after, maybe around 50k tokens.

Sending Continue did work, but it failed again after taking a turn. I tried this twice more and it does seem that for now the session is continuing on.

What is the expected behavior?

Don't die mid session.

Ideally we'd also have more error resistant retries with exponential back-off to something like 20 retries over 10 minutes.

Additional information

No response

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appIssues related to the Codex desktop appIssues related to the Codex desktop app

bugSomething isn't workingSomething isn't working

connectivityIssues involving networking or endpoint connectivity problems (disconnections)Issues involving networking or endpoint connectivity problems (disconnections)

sessionIssues involving session (thread) management, resuming, forking, naming, archivingIssues involving session (thread) management, resuming, forking, naming, archiving

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