# Anthropic: Major incident: Elevated errors for Claude Sonnet 5

**Summary:** Claude Sonnet 5 requests experienced elevated errors affecting claude.ai, Claude API (api.anthropic.com), Claude Code and Claude Cowork. Anthropic rated the incident major; it started at 2026-09-02 21:17 UTC and was resolved after 26 min. The resolution update separately reported customer impact from 21:05 UTC to 21:19 UTC. _(machine-written, sol)_
- Kind: Major incident · Label: outage (model (Jev))
- Changed: 2026-09-02 21:17 UTC · Detected: 2026-10-17 18:21 UTC
- [Source: https://stspg.io/9dgzwz3ymz42](https://stspg.io/9dgzwz3ymz42)
- [Company: Anthropic](https://rewindex.com/company/anthropic.md)
- Versions: before (none: first archived) → after incident\_version:1/ls6bn1x81m0w@e891b5899263
- Change 1 of 1 for this incident

## What changed

**1. Added: Title**

```diff
+ Elevated errors for Claude Sonnet 5
```

**2. Added: Impact**

```diff
+ major
```

**3. Added: Status**

```diff
+ resolved
```

**4. Added: Start time**

```diff
+ 2026-09-02 21:17 UTC
```

**5. Added: Resolved time**

```diff
+ 2026-09-02 21:44 UTC
```

**6. Added: Affected components**

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

**7. Added: Update** (investigating) · 2026-09-02 21:17 UTC

```diff
+ We are investigating elevated errors on requests to Claude Sonnet 5. We will provide an update as soon as possible.
```

**8. Added: Update** (resolved) · 2026-09-02 21:44 UTC

```diff
+ The issue affecting Claude Sonnet 5 has been resolved. Impact occurred from 2:05pm PT / 21:05 UTC to 2:19pm PT / 21:19 UTC.
```

## History of this incident

| When (UTC) | Change | Label |
| --- | --- | --- |
| 2026-09-02 21:17 UTC | Major incident: Elevated errors for Claude Sonnet 5 (this change) | outage |

All Anthropic changes: [timeline](https://rewindex.com/company/anthropic/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/i4f2cf5451fb3bf · Markdown: https://rewindex.com/change/i4f2cf5451fb3bf.md · JSON: https://rewindex.com/api/v1/changes/i4f2cf5451fb3bf · Generated 2026-10-18T00:37:39.850Z