Stack AI Partial Outage - April 28, 2026

Type: Incident Duration: 3 days, 21 hours and 57 minutes Affected Components: Anthropic → Claude API (api.anthropic.com) Apr 28, 17:51:36 GMT+0 - Identified - We have identified an issue resulting in elevated errors on the Anthropic API, as well as issues accessing Claude.ai, including log-in paths for Claude Code. We are working to resolve these issues, and will provide an update as soon as possible. Apr 28, 19:15:52 GMT+0 - Resolved - This incident has been resolved. Apr 28, 18:59:47 GMT+0 - Monitoring - We are seeing success rates across all services return to normal, and are monitoring closely to prevent any further issues. Impact occurred from 17:34–18:52 UTC. Apr 28, 18:33:55 GMT+0 - Identified - We are continuing to work to resolve the issues preventing users from accessing Claude.ai, and causing elevated authentication errors for requests to the API and Claude Code. Apr 28, 17:41:55 GMT+0 - Investigating - We are investigating an issue preventing users from reaching Claude.ai, and will provide an update as soon as possible.