Changes Claude Elevated errors for Claude Sonnet 5.5

Claude: Major incident: Elevated errors for Claude Sonnet 5.5

Major incidentoutage (model (Jev), 99%)Changed 2026-10-27 09:14 UTCDetected 2026-10-27 09:24 UTCstatus.claude.com

Summary

Claude reported elevated errors on Claude Sonnet 5.5 requests affecting claude.ai, Claude API - api.anthropic.com, Claude Code, and Claude Cowork, with major impact. The incident started at 2026-10-27 09:14 UTC and was still open when archived, open for 0 min at the last update; investigation was ongoing, with no cause or fix stated.

Machine-written from the diff below (Sol; type: incident outage). Check the diff before relying on it.

Incident page: the full timeline of updates

What changed

~~Struck in red~~ is what Claude removed; blue is what they added. Muted text is unchanged context.

AddedTitle#1

not present

Elevated errors for Claude Sonnet 5.5

AddedImpact#2

not present

major

AddedStatus#3

not present

investigating

AddedStart time#4

not present

2026-10-27 09:14 UTC

AddedAffected components#5

not present

claude.ai, Claude API - api.anthropic.com, Claude Code, Claude Cowork

AddedUpdateinvestigating2026-10-27 09:14 UTC#6

not present

We are investigating elevated errors on requests to Claude Sonnet 5.5. We will provide an update as soon as possible.

First version of this incident archived by Rewindex. View the live incident (opens in new tab).

Archive proof

Rewindex commits each version of an incident it captures to a daily checkpoint, chains it to the day before, and has the checkpoint timestamped by FreeTSA and DigiCert. That proves this record existed by then and has not been changed since, by anyone, Rewindex included.

How the archive is checked, and what it cannot prove.

Oct 27
After captured 09:24 UTC
In the 2026-10-27 checkpoint, timestamped by DigiCert and FreeTSA on Oct 28, 00:41 UTC. Record hash 8a487cf27ebcf554…
Download proof

History of this incident

Tuesday, October 27

3 incident changes

Normal progress
10:04Incident
Incident updateElevated errors for Claude Sonnet 5.5
Normal progress
09:43Incident
Incident updateElevated errors for Claude Sonnet 5.5
Outage
09:14Major incident
Elevated errors for Claude Sonnet 5.5this change
Claude reported elevated errors on Claude Sonnet 5.5 requests affecting claude.ai, Claude API - api.anthropic.com, Claude Code, and Claude Cowork, with major impact. The incident started at 2026-10-27 09:14 UTC and was still open when archived, open for 0 min at the last update; investigation was ongoing, with no cause or fix stated.

Cite this

Major incident: Elevated errors for Claude Sonnet 5.5 on Claude’s status page, changed 2026-10-27 09:14 UTC (change 1 of 3).

Title: Major incident: Elevated errors for Claude Sonnet 5.5
Vendor: Claude
Date: 2026-10-27 09:14 UTC
URL: https://rewindex.com/change/i3bce94de1b9be0

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