Outage in Anthropic
Elevated errors for multiple models
Resolved MajorIncident Report
Summary AI Generated
Anthropic experienced elevated API errors across multiple Claude models — including Mythos/Fable 5.1, Mythos/Fable 5, Opus 5, Opus 4.8, and Opus 4.6 — affecting both claude.ai and api.anthropic.com for approximately 3 hours. Users encountered 529 Overloaded errors, indicating server-side capacity issues that disrupted API requests. A fix was deployed and the incident was fully resolved by 16:16 UTC on September 3, 2026.
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.
Trusted by 1,000+ teams
The Status Page Aggregator with Early Outage Detection
Stop finding out about outages from your users. Monitor 6,320+ cloud services and get alerted the second something breaks.
Latest Updates ( sorted recent to last )
RESOLVED
2 days ago - at 09/03/2026 04:23PM
The issue affecting Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 has been resolved. Impact has ended as of 9:16 PT / 16:16 UTC.
MONITORING
2 days ago - at 09/03/2026 04:06PM
A fix has been deployed for Claude Mythos 5.1, Claude Fable 5.1, and Claude Opus 5 and we are monitoring for recovery.
IDENTIFIED
2 days ago - at 09/03/2026 03:25PM
The only affected models right now are Opus 4.8 and Opus 5. The rest of the models have recovered to baseline error rate.
IDENTIFIED
2 days ago - at 09/03/2026 02:49PM
We are continuing to work on a fix for this issue.
IDENTIFIED
2 days ago - at 09/03/2026 01:50PM
An exhaustive list of affected models: Mythos/Fable 5.1, Mythos/Fable 5, Opus 5, Opus 4.8, Opus 4.6.
IDENTIFIED
2 days ago - at 09/03/2026 01:41PM
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.
INVESTIGATING
2 days ago - at 09/03/2026 01:26PM
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.
Latest Anthropic outages
Elevated errors for Claude Sonnet 5 - 2 days ago
Elevated errors for Claude Sonnet 5 - 3 days ago
Delays in credit purchases - 4 days ago
The Status Page Aggregator with Early Outage Detection
With IsDown, you can monitor all your critical services' official status pages from one centralized dashboard and receive instant alerts the moment an outage is detected. Say goodbye to constantly checking multiple sites for updates and stay ahead of outages with IsDown.
Start free trialNo credit card required · Cancel anytime · 6320 services available
Integrations with
