Incident report · read from Anthropic's status page

Anthropic incident: Elevated errors for Claude Sonnet 5.5

Resolved after 41 m (27 Oct 2026, 15:09–15:50 UTC), impact major, affecting Claude Cowork, Claude API (api.anthropic.com), claude.ai and Claude Code.

Timeline

1. 27 Oct 2026 at 15:09 UTC identified

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

2. 27 Oct 2026 at 15:50 UTC resolved

   The issue affecting claude.ai, the Claude API, Claude Code, and Claude Cowork has been resolved. Impact occurred from 07:42 PT / 14:42 UTC to 08:17 PT / 15:17 UTC.

Affected components

• Claude Cowork: partial outage for 41 m
• Claude API (api.anthropic.com): partial outage for 41 m
• claude.ai: partial outage for 41 m
• Claude Code: partial outage for 41 m

What the crowd did

• 0 clicks, 3 zombies at their worst, 0 breaches, over 43 m — the siege in full

That is this site's own record of the crowd at Anthropic's gate, not anything Anthropic published.

Source

Anthropic's own report of this incident, on Anthropic's status page. This page is a record of Anthropic's own report; where the two disagree, theirs is right.

Last checked 30 Oct 2026 at 15:35 UTC.

Must Have AI is a parody and is not affiliated with, endorsed by or connected to OpenAI, Anthropic or Google. Every outage shown here is read from the provider's own public status page.