Anthropic outage: Elevated errors for Claude Sonnet 5.5

Affected components

• Claude API (api.anthropic.com)
• Claude Code
• Claude Cowork
• claude.ai

1. investigatingOct 27, 2026, 09:14 UTC

   We are investigating elevated errors on requests to Claude Sonnet 5.5. We will provide an update as soon as possible.

What APIStatus.watch saw

• Oct 27, 2026, 09:19 UTCoperational → degraded
• Oct 27, 2026, 09:39 UTCdegraded → operational

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How often does Anthropic have incidents?

Anthropic reported 53 incidents in the last 90 days, 28 of them major or critical. A typical incident lasted 1h 7m. See Anthropic's uptime and incident history