# Claude outage on 27 October 2026

> On 27 October, Claude had a major outage with elevated errors on requests to Claude Sonnet 5.5, affecting claude.ai, the Claude API, Claude Code and Claude Cowork. The incident was open on the status page for 41 minutes, from 15:09 to 15:50 UTC, but the status page's final update said the impact actually ran from 14:42 to 15:17 UTC, before the incident was opened. Blackbaud, OpenAI, Musixmatch, Thomson Reuters Legal and Procore also reported problems around the same time, and this was Claude's fourth outage in four days.

- Service: [Claude](https://stackpulse.app/services/claude.md)
- Severity: major_outage
- Title on the status page: Elevated errors for Claude Sonnet 5.5
- Started: 2026-10-27 15:09 UTC
- Ended: 2026-10-27 15:50 UTC
- Lasted: 41 min
- Incident open on the status page: 15:09–15:50 UTC
- The status page's incident: https://stspg.io/39x7qh3sd7bd
- Page: https://stackpulse.app/services/claude/outages/2026-10-27-1509

## What broke when (UTC)

| Component | Status | From | To |
|---|---|---|---|
| claude.ai | partial outage | 2026-10-27 15:09 | 2026-10-27 15:50 |
| Claude API (api.anthropic.com) | partial outage | 2026-10-27 15:09 | 2026-10-27 15:50 |
| Claude Code | partial outage | 2026-10-27 15:09 | 2026-10-27 15:50 |
| Claude Cowork | partial outage | 2026-10-27 15:09 | 2026-10-27 15:50 |

## At the same time

- [Blackbaud](https://stackpulse.app/services/blackbaud.md): issue from 2026-10-27 14:36 UTC
- [OpenAI](https://stackpulse.app/services/openai.md): issue from 2026-10-27 15:02 UTC
- [Musixmatch](https://stackpulse.app/services/musixmatch.md): issue from 2026-10-27 15:19 UTC
- [Thomson Reuters Legal](https://stackpulse.app/services/thomson-reuters-legal.md): major_outage from 2026-10-27 15:20 UTC
- [Procore](https://stackpulse.app/services/procore.md): issue from 2026-10-27 15:48 UTC

Problems at the same time are a clue, never proof that one caused another.

Stackpulse isn't affiliated with Claude.