Artificial intelligence lab Anthropic is investigating an active service disruption affecting multiple core platforms. The incident began on Friday morning, November 13, 2026, preventing users from logging into their accounts.

The company posted an official incident notice to its public status dashboard. The advisory confirmed that an authentication issue is under active investigation.

Authentication Failure Knocks Out Claude Services

The disruption officially began at 09:58 UTC on November 13. Anthropic designated the event an active incident across its network monitors.

In its initial advisory, the company stated: "We are investigating an issue with users authenticating to Claude.ai and Claude Code. We will provide an update as soon as possible."

The authentication failure prevents identity checks during login attempts. Visitors attempting to open the web platform encounter failed sign-in screens and session errors.

Official Status Dashboard Details Affected Services

Anthropic's system status report lists specific operational impacts across individual product components:

  • claude.ai: Categorized as experiencing a Major Outage.
  • Claude Code: Listed under a Partial Outage affecting developer terminal workflows.
  • Claude Console (platform.claude.com): Operating under a Partial Outage for account management.
  • Claude Cowork: Displaying Degraded Performance.

Meanwhile, the core Claude API at api.anthropic.com remains fully operational. Anthropic-managed models on Amazon Web Services, Google Cloud, Microsoft Foundry, and Claude for Government also report normal operations.

Upstream Connector Issue Remains Active

Friday's login problem coincides with an ongoing connector incident logged the previous day. Anthropic identified elevated errors on its Microsoft 365 connector at 17:52 UTC on November 12.

The company confirmed that the connector issue originated with an upstream Microsoft service disruption. Mail, calendar, and search integrations inside Claude for Outlook continue to experience elevated error rates while Microsoft restarts affected servers.

The two events involve separate technical infrastructure, but both remain listed as open incidents on Anthropic’s monitoring page.

Current Status and Next Updates

Anthropic has not listed a projected restoration time on its status page. The company noted that engineers are investigating the authentication layer and will post updates as new information becomes available.

Users experiencing login failures are advised to monitor the official status feed for real-time recovery notices.