# Elevated errors for Claude Sonnet 5.5 and other models

- Provider: [Anthropic](https://down.guide/anthropic)
- Level: confirmed
- Impact: Partial outage
- lasted 1h 39m
- started 2026-10-25 06:14 UTC
- claude.ai, Claude API (api.anthropic.com), Claude Code +1
- id: DWN-c9b731d6b0
- Official page: https://stspg.io/s3wd6gmdsdhn

## Root cause
> We have identified the cause of elevated errors on requests to Claude Sonnet 5.

[Postmortem](https://stspg.io/s3wd6gmdsdhn)

## Updates from Anthropic
### 2026-10-25 06:14 UTC: investigating
We are investigating elevated errors on requests to Claude Mythos 5.1, Claude Fable 5.1, Claude Opus 5.5, Claude Sonnet 5.5, and Claude Haiku 5.5. We will provide an update as soon as possible.

### 2026-10-25 06:27 UTC: identified
We have identified the cause of elevated errors on requests to Claude Sonnet 5.5 and are working on a fix. We will provide an update as soon as possible.

### 2026-10-25 06:35 UTC: monitoring
A fix has been deployed for the issue affecting Claude services and we are monitoring for recovery.

### 2026-10-25 07:53 UTC: resolved
The issue affecting Claude services has been resolved. Impact occurred from 23:05 PT on October 24 / 06:05 UTC on October 25 to 23:35 PT on October 24 / 06:35 UTC on October 25.

From the builder: does your app depend on Anthropic? [Sazabi](https://www.sazabi.com/?utm_source=down-guide&utm_medium=markdown&utm_content=anthropic) detects problems in your own logs without hand-written monitors, and you can ask it in plain language which errors mention Anthropic.

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