ChatGPT Plus OAuth returns 429 quota exceeded for third-party tool API calls

What this error means

429 quota exceeded — ChatGPT Plus OAuth authentication succeeds but third-party Codex calls to openai-codex/gpt-5.4 return 429 despite active Plus subscription is a OpenAI API failure pattern reported for developers trying to understand why chatgpt plus quota does not apply to third-party api calls; determine if separate credits required or if quota routing between first-party and third-party oauth contexts is a product bug. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

GitHub Issue #2951 in openai/openai-python (opened Mar 10 2026, AllinAI20260127). OAuth login works perfectly, but API calls via third-party tools get 429 quota. Directly affects paying Plus subscribers using non-Official clients. High commercial impact since it involves billing/quota on a paid subscription product. Category mapping: OpenAI API (quota/billing error on paid API service).

Common causes

• GitHub Issue #2951 in openai/openai-python (opened Mar 10 2026, AllinAI20260127). OAuth login works perfectly, but API calls via third-party tools get 429 quota. Directly affects paying Plus subscribers using non-Official clients. High commercial impact since it involves billing/quota on a paid subscription product. Category mapping: OpenAI API (quota/billing error on paid API service).

Quick fixes

1. Confirm the exact error signature matches 429 quota exceeded — ChatGPT Plus OAuth authentication succeeds but third-party Codex calls to openai-codex/gpt-5.4 return 429 despite active Plus subscription.
2. Check the OpenAI API account, local tool state, and provider configuration involved in the failing workflow.
3. Reduce request pressure, check quota or plan limits, and retry with backoff instead of immediate repeated requests.

Platform/tool-specific checks

• Verify the command, editor, extension, or API client that produced the error.
• Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
• Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

1. Capture the exact error message and the command, editor action, or request that triggered it.
2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
3. Review the source evidence below and compare it with your environment.
4. Apply one change at a time and rerun the smallest failing action.
5. Keep the working fix documented for the team or deployment environment.

How to prevent it

• Keep provider/tool configuration documented.
• Record non-secret diagnostics such as tool version, provider name, model name, and command path.
• Add a lightweight check before CI or production workflows depend on the tool.

Sources checked

• https://github.com/openai/openai-python/issues/2951

Evidence note: GitHub Issue #2951 in openai/openai-python (opened Mar 10 2026, AllinAI20260127). OAuth login works perfectly, but API calls via third-party tools get 429 quota. Directly affects paying Plus subscribers using non-Official clients. High commercial impact since it involves billing/quota on a paid subscription product. Category mapping: OpenAI API (quota/billing error on paid API service).

Related errors

• OpenAI API

FAQ

What should I check first?

Start with the exact 429 quota exceeded — ChatGPT Plus OAuth authentication succeeds but third-party Codex calls to openai-codex/gpt-5.4 return 429 despite active Plus subscription text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed OpenAI API workflow until the root cause is understood.

Is this guaranteed to have one fix?

No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.

How do I know the fix worked?

Rerun the same command, editor action, or request. The fix is working when that action completes without 429 quota exceeded — ChatGPT Plus OAuth authentication succeeds but third-party Codex calls to openai-codex/gpt-5.4 return 429 despite active Plus subscription.