downClaude outage on 2026-10-27: Elevated errors for Claude Sonnet 5.5
Claude published an official incident report on 2026-10-27 (UTC): Elevated errors for Claude Sonnet 5.5.
The provider classified the incident's impact as major. This brief is based on an official incident report, not estimated search activity.
The provider's latest collected incident status is resolved. This status was checked at 2026-11-03 00:10:27 UTC.
What the provider confirmed
- Incident
- Elevated errors for Claude Sonnet 5.5
- First provider report
- 2026-10-27 15:09:08 UTC
- Provider impact classification
- major
- Resolution marker
- 2026-10-27 15:50:17 UTC
The first provider-report time is not necessarily the moment the disruption began. These timestamps do not establish the full duration of the outage.
Affected components
- claude.ai
- Claude API (api.anthropic.com)
- Claude Code
- Claude Cowork
Official incident timeline
- identified
- resolved
This is a summary of the provider's recorded status changes. Consult the official incident report for its complete narrative and subsequent corrections.
What to check if you are still affected
Compare your error and the affected product with the components named above. Check the provider's latest notice and the live service page. Test another browser or network when practical, and avoid assuming that a resolved provider incident guarantees recovery for every session or integration.
For integrations, inspect the actual response code before retrying. Repeatedly submitting the same action can duplicate work. Preserve the time and error message when contacting the provider's support team.
About this report
Claude official incident report · collected 2026-11-03 00:10:27 UTC. The geographic reach, affected-user count, root cause, and complete downtime duration are not independently established by this brief.
New incident articles require a major or critical incident with explicit disruption evidence. Read our methodology.
Automatically assembled from provider evidence. This article used the fixed evidence template. This report updates when a changed official incident is collected.