Anthropic change history: Elevated errors for Claude Sonnet 5

Claude Sonnet 5 requests experienced elevated errors across claude.ai, Claude API (api.anthropic.com), Claude Code and Claude Cowork, with major impact. The incident started at 2026-09-03 12:37 UTC and was resolved at 2026-09-03 12:56 UTC; the reported duration was 18 min. Anthropic implemented a fix and monitored results before resolution.