Major impactResolvedAI/ML

Claude outage: Intermittent error spikes for Claude Mythos 5.1 and Claude Fable 5.1

Claude reported this major-impact incident on its official status page on Sep 15, 2026, 09:48 UTC. It was resolved after 1h 26m.

Right now Claude is operational. Live Claude status →

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Sep 15, 2026, 09:48 UTC
started
Sep 15, 2026, 11:14 UTC
resolved
1h 26m
duration
Major
impact

Affected components

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

Timeline

updates from Claude's status page ↗
  1. resolvedSep 15, 2026, 11:14 UTC

    A fix has been deployed for Claude Mythos 5.1 and Claude Fable 5.1 and we are monitoring to ensure it has resolved the issue.

  2. monitoringSep 15, 2026, 10:50 UTC

    A fix has been deployed for Claude Mythos 5.1 and Claude Fable 5.1 and we are monitoring to ensure it has resolved the issue.

  3. investigatingSep 15, 2026, 09:52 UTC

    We are investigating elevated errors on requests to Claude Mythos 5.1 and Claude Fable 5.1. We will provide an update as soon as possible.

  4. investigatingSep 15, 2026, 09:48 UTC

    We are investigating elevated errors on requests to Claude Mythos 5.1 and Claude Fable 5.1. We will provide an update as soon as possible.

What APIStatus.watch saw

  • Sep 15, 2026, 09:50 UTCoperational → degraded
  • Sep 15, 2026, 11:15 UTCdegraded → operational

Other services with incidents at the same time

Overlapping incidents aren't necessarily related.

How often does Claude have incidents?

Claude reported 85 incidents in the last 90 days, 32 of them major or critical. A typical incident lasted 1h 7m. See Claude's uptime and incident history

← Previous: Elevated errors for Claude Mythos 5.1 and Claude Fable 5.1 (Sep 11, 2026)Next: Elevated errors for multiple models (Sep 22, 2026) →
Claude outage on Sep 15, 2026: Intermittent error spikes for Claude Mythos 5.1 and Claude Fable 5.1 · APIStatus.watch