gpt-5.4 and gpt-5.3-codex unavailable via Codex extention on VSC and Codex App when using ChatGPT account

[zuna107]

What issue are you seeing?

As of March 10, 2026, the models gpt-5.4 and gpt-5.3-codex are no longer accessible when using Codex with a ChatGPT account.

When selecting either model in Codex App or the VSCode Codex extension and sending a prompt, the request fails with the following error:

{"detail":"The 'gpt-5.4' model is not supported when using Codex with a ChatGPT account."}

The same behavior occurs with gpt-5.3-codex.
These models were confirmed working on March 9. Older models such as gpt-5.2 still function normally.
The issue has been reported by multiple users across Free and Business plans, suggesting a possible backend regression or access policy change.

What steps can reproduce the bug?

1. Open Codex App or VSCode with the Codex extension installed.
2. Log in using a ChatGPT account.
3. Select the model "gpt-5.4" or "gpt-5.3-codex".
4. Send any prompt.

Result:
The request fails with the error:

{"detail":"The 'gpt-5.4' model is not supported when using Codex with a ChatGPT account."}

Note:
Older models such as gpt-5.2 continue to work normally.

What is the expected behavior?

No response

Additional information

No response

[github-actions]

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

• The GPT-5.3-Codex model does NOT WORK in PAID ACCOUNT #14331
• Codex 5.4 / 5.3-codex models fail with “not supported for ChatGPT account” error #14190
• {"detail":"The 'gpt-5.3-codex' model is not supported when using Codex with a ChatGPT account."} #14306
• The ('gpt-5.4', 'gpt-5.3-codex') model is not supported when using Codex with a ChatGPT account. #14181
• Error Message "'gpt-5.3-codex' model is not supported" in VS Code Extension #14237

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[etraut-openai]

Are you using a free plan, or a paid plan? If free, then this is expected. See #14181 for details.

If you are using a paid plan, then this is not expected. We've had a few reports of this from other users, but we're looking for additional clues that might explain the problem. If you're on a paid plan, please use the /feedback slash command to upload your logs and post the thread ID below so we can investigate.

[aethnova]

Just resolved this on my end. Turned out my ChatGPT Plus subscription had expired — the error disappeared immediately after I renewed it.

If you're seeing this error, check your subscription status first. When the subscription lapses, the OAuth token loses access to gpt-5.4 and gpt-5.3-codex, but gpt-5.2 still works (likely available on Free tier). The error message doesn't mention subscription at all, which makes it very misleading.

This may not be the cause for everyone, but worth checking before assuming it's a backend regression.

[manel00]

then why this error? it must be handled...