Elevated errors for Claude Mythos 5.1 and Claude Fable 5.1
View the provider incident record →Current answer
Anthropic (Claude) experienced a major incident: Elevated errors for Claude Mythos 5.1 and Claude Fable 5.1. ServiceAlert observed recovery on Sep 11, 2026.
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Incident Lifecycle
Affected Components
claude.ai
Claude API (api.anthropic.com)
Claude Code
Claude Cowork
Incident Timeline
Monitoring
A fix has been deployed for the issue affecting Claude services and we are monitoring for recovery.
Sep 11, 2026 at 2:28 PM UTC
Monitoring
A fix has been deployed for Claude Mythos 5.1 and Claude Fable 5.1 and we are monitoring for recovery.
Sep 11, 2026 at 2:28 PM UTC
Identified
We have identified the cause of elevated errors on requests to Claude Mythos 5.1 and Claude Fable 5.1 and are working on a fix. We will provide an update as soon as possible.
Sep 11, 2026 at 2:21 PM UTC
Investigating
We are investigating elevated errors on requests to Claude Fable 5.1 and Claude Mythos 5.1. We will provide an update as soon as possible.
Sep 11, 2026 at 2:19 PM UTC
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