# Claude: Major incident: Elevated errors for multiple models

**Summary:** Claude reported major elevated request errors affecting Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5. The incident started at 2026-09-22 00:57 UTC and resolved at 2026-09-22 02:35 UTC, lasting 1 h 37 min; the final update reported customer impact from 00:50 UTC to 02:10 UTC. _(machine-written, sol)_
- Kind: Major incident · Label: outage (model (Jev))
- Changed: 2026-09-22 00:57 UTC · Detected: 2026-10-17 18:22 UTC
- [Source: https://stspg.io/90s4l9yywzbk](https://stspg.io/90s4l9yywzbk)
- [Company: Claude](https://rewindex.com/company/claude.md)
- Versions: before (none: first archived) → after incident\_version:6/7g1qpkyz5gxh@35b4cebe7765
- Change 1 of 1 for this incident

## What changed

**1. Added: Title**

```diff
+ Elevated errors for multiple models
```

**2. Added: Impact**

```diff
+ major
```

**3. Added: Status**

```diff
+ resolved
```

**4. Added: Start time**

```diff
+ 2026-09-22 00:57 UTC
```

**5. Added: Resolved time**

```diff
+ 2026-09-22 02:35 UTC
```

**6. Added: Affected components**

```diff
+ claude.ai, Claude API (api.anthropic.com), Claude Code, Claude Cowork
```

**7. Added: Update** (investigating) · 2026-09-22 00:57 UTC

```diff
+ We are investigating elevated errors on requests to Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5. We will provide an update as soon as possible.
```

**8. Added: Update** (identified) · 2026-09-22 01:17 UTC

```diff
+ We have identified the cause of elevated errors on requests to Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 and are working on a fix. We will provide an update as soon as possible.
```

**9. Added: Update** (identified) · 2026-09-22 01:35 UTC

```diff
+ We are continuing to work to resolve errors affecting some models. At this time, requests to Claude Fable 5 and 5.1 and Mythos 5 and 5.1 have returned to normal success rates. We are working to resolve remaining errors affecting Claude Opus 5, and will provide an additional update shortly.
```

**10. Added: Update** (monitoring) · 2026-09-22 02:11 UTC

```diff
+ We have seen success rates return to normal across affected models, and are monitoring closely to ensure no further issues.
```

**11. Added: Update** (resolved) · 2026-09-22 02:35 UTC

```diff
+ This issue has been resolved. Impact occurred from 5:50pm PT / 00:50 UTC to 7:10pm PT / 02:10 UTC.
```

## History of this incident

| When (UTC) | Change | Label |
| --- | --- | --- |
| 2026-09-22 00:57 UTC | Major incident: Elevated errors for multiple models (this change) | outage |

All Claude changes: [timeline](https://rewindex.com/company/claude/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/i39bc99a428c716 · Markdown: https://rewindex.com/change/i39bc99a428c716.md · JSON: https://rewindex.com/api/v1/changes/i39bc99a428c716 · Generated 2026-10-18T03:31:46.899Z