Outage in Anthropic
Elevated errors for Claude Fable 5.1, Sonnet 5.5, and Haiku 5.5
Resolved MajorIncident Report
Summary AI Generated
Anthropic experienced elevated error rates across multiple Claude models — Fable 5.1, Sonnet 5.5, Haiku 5.5, and Opus 5.5 fast mode — affecting both claude.ai and api.anthropic.com for approximately 31 minutes on October 23, 2026. The root cause was identified and a fix was applied, with success rates returning to normal before the incident was formally resolved.
We are investigating elevated errors on requests to Claude Fable 5.1. We will provide an update as soon as possible.
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Latest Updates ( sorted recent to last )
RESOLVED
6 days ago - at 10/24/2026 12:11AM
The issue affecting Claude models has been resolved. Impact occurred from 16:28 PT / 23:28 UTC on October 23 to 16:59 PT / 23:59 UTC on October 23.
MONITORING
6 days ago - at 10/23/2026 11:54PM
We are seeing success rates return to normal for all affected models, and are continuing to monitor to ensure no further issues.
IDENTIFIED
6 days ago - at 10/23/2026 11:39PM
We have identified the cause of elevated errors on requests to Claude Fable 5.1, Sonnet 5.5, and Haiku 5.5, as well as fast mode requests to Opus 5.5 and are working on a fix. We will provide an update as soon as possible.
INVESTIGATING
6 days ago - at 10/23/2026 11:37PM
We are investigating elevated errors on requests to Claude Fable 5.1. We will provide an update as soon as possible.
Latest Anthropic outages
Elevated errors affecting the Gmail connector - 2 days ago
Elevated errors for Claude Sonnet 5.5 - 3 days ago
Elevated errors for Claude Sonnet 5.5 - 3 days ago
Elevated errors for Claude Fable 5.1 - 5 days ago
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