Changes / Claude / Elevated errors for multiple models
Claude: Major incident: Elevated errors for multiple models
Summary
Claude reported major elevated request errors affecting Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5. The incident started at 2026-09-22 00:57 UTC and resolved at 2026-09-22 02:35 UTC, lasting 1 h 37 min; the final update reported customer impact from 00:50 UTC to 02:10 UTC.
Machine-written from the diff below (Sol; type: incident outage). Check the diff before relying on it.
What changed
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After: Elevated errors for multiple models
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After: major
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After: resolved
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After: 2026-09-22 00:57 UTC
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After: 2026-09-22 02:35 UTC
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After: claude.ai, Claude API (api.anthropic.com), Claude Code, Claude Cowork
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After: We are investigating elevated errors on requests to Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5. We will provide an update as soon as possible.
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After: We have identified the cause of elevated errors on requests to Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 and are working on a fix. We will provide an update as soon as possible.
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After: We are continuing to work to resolve errors affecting some models. At this time, requests to Claude Fable 5 and 5.1 and Mythos 5 and 5.1 have returned to normal success rates. We are working to resolve remaining errors affecting Claude Opus 5, and will provide an additional update shortly.
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After: We have seen success rates return to normal across affected models, and are monitoring closely to ensure no further issues.
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After: This issue has been resolved. Impact occurred from 5:50pm PT / 00:50 UTC to 7:10pm PT / 02:10 UTC.
First version of this incident archived by Rewindex. View the live incident (opens in new tab).
History of this incident
| When (UTC) | Change | Kind |
|---|---|---|
| Major incident: Elevated errors for multiple models (this change) Claude reported major elevated request errors affecting Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5. The incident started at 2026-09-22 00:57 UTC and resolved at 2026-09-22 02:35 UTC, lasting 1 h 37 min; the final update reported customer impact from 00:50 UTC to 02:10 UTC. | Major incident |