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Incident archive

Claude outage September 11, 2026

Elevated errors for Claude Mythos 5.1 and Claude Fable 5.1

Claude claude.ai was down for 17 min on September 11, 2026.

Claude recorded a major-impact incident affecting claude.ai, Claude API (api.anthropic.com), Claude Code, Claude Cowork on September 11, 2026. It ran for 17 min — 50 min shorter than the archive median of 1 h 7 min.

Started
September 11, 2026, 14:19 UTC
Resolved
September 11, 2026, 14:37 UTC
Duration
17 min
Impact
Major

What was affected?

How long did it last?

  1. September 11, 2026, 14:19 UTCinvestigatingT+0
  2. September 11, 2026, 14:21 UTCidentifiedT+1 min
  3. September 11, 2026, 14:28 UTCmonitoringT+8 min
  4. September 11, 2026, 14:28 UTCmonitoringT+9 min
  5. September 11, 2026, 14:37 UTCresolvedT+17 min

Has this happened before?

This was incident 9 of 10 recorded in September 2026, totalling 109 h 47 min of reported disruption across all Claude components that month. claude.ai was affected by 19 other recorded incidents in the 30 days before this one started. The previous incident touching claude.ai started on September 3, 2026. These comparisons are drawn from our archive, which starts on July 14, 2026. See the full outage history.

Summarized by Claude Network from Claude Status. Last verified .