# ChatGPT: Major incident: Authentication errors for some API users

**Summary:** _summary pending_
- Kind: Major incident · Label: major (vendor)
- Changed: 2026-10-20 16:35 UTC · Detected: 2026-10-21 22:43 UTC
- [Source: https://status.openai.com/incidents/01M5G9QQ9V4CYDWFRYF9BWZ5GG](https://status.openai.com/incidents/01M5G9QQ9V4CYDWFRYF9BWZ5GG)
- [Company: ChatGPT](https://rewindex.com/company/chatgpt.md)
- Versions: before (none: first archived) → after incident\_version:5/01M5G9QQ9V4CYDWFRYF9BWZ5GG@73af2effc3ab
- Change 1 of 2 for this incident

Incident page (full timeline): [Authentication errors for some API users](https://rewindex.com/company/chatgpt/incidents/01M5G9QQ9V4CYDWFRYF9BWZ5GG.md)
## What changed

**1. Added: Title**

```diff
+ Authentication errors for some API users
```

**2. Added: Impact**

```diff
+ major
```

**3. Added: Status**

```diff
+ resolved
```

**4. Added: Start time**

```diff
+ 2026-10-20 16:35 UTC
```

**5. Added: Resolved time**

```diff
+ 2026-10-20 17:35 UTC
```

**6. Added: Update** (investigating) · 2026-10-20 16:35 UTC

```diff
+ Some API users near Illinois experienced authentication errors.
```

**7. Added: Update** (resolved) · 2026-10-20 17:35 UTC

```diff
+ On October 20, from 9:35 to 10:35 a.m. PDT, some API users near Illinois experienced authentication errors. We rolled back a configuration change, and service was restored.
```

## History of this incident

| When (UTC) | Change | Label |
| --- | --- | --- |
| 2026-10-20 16:35 UTC | Major incident: Authentication errors for some API users (this change) | major |
| 2026-10-21 23:13 UTC | [Incident silently edited: Authentication errors for some users](https://rewindex.com/change/r1bda5be66b8023.md) |  |

Next: [change](https://rewindex.com/change/r1bda5be66b8023.md) · All ChatGPT changes: [timeline](https://rewindex.com/company/chatgpt/changes.md)
_Diff excerpts are shown on normalized text: dates, counters and tokens appear as ‹date›, ‹count›, ‹tok›; noise-only edits are hidden. Rewindex shows the changed passages, not a copy of the page._


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Canonical: https://rewindex.com/change/i01f64aedfdbfc7 · Markdown: https://rewindex.com/change/i01f64aedfdbfc7.md · JSON: https://rewindex.com/api/v1/changes/i01f64aedfdbfc7 · Generated 2026-10-22T06:03:42.236Z