# Claude Suffers Login Outage Across Claude.ai and Claude Code While Microsoft 365 Connector Stays Down > Source: > Published: 2026-11-13 10:02:46+00:00 *Claude is having a bad Friday. Users cannot reliably log in to Claude.ai and Claude Code, and the Microsoft 365 connector has been failing for most requests since Thursday afternoon. The two problems have different causes, and only one of them is Anthropic's to fix.* - Anthropic opened an incident at 09:58 UK time on Friday for users authenticating to Claude.ai and Claude Code, and its status page showed Claude.ai in a major outage - The Microsoft 365 connector has been failing since Thursday evening because of a Microsoft 365 service incident, not an Anthropic fault - Claude for Outlook is affected, and mail, calendar and search tools in the connector were still failing at the last update - Anthropic has not given a cause or a fix time for the login problem At 09:58 UK time on 13 November, Anthropic's status page listed a new incident titled "Elevated errors on claude.ai, Claude Code, and platform.claude.com". The company said it was investigating an issue with users authenticating to Claude.ai and Claude Code, and would provide an update as soon as possible. When we checked a few minutes later, the page showed Claude.ai in a major outage, the Claude Console and Claude Code in partial outages, and Claude Cowork degraded. ## The login outage The incident was still at the investigating stage when we checked. Anthropic had not published a cause, an estimate of how many users were affected, or a time for a fix. Anything beyond that would be a guess, so we will not offer one. Users who cannot sign in to Claude Code cannot work, which is why a login failure matters more than a slow response. ## The Microsoft 365 connector The second incident started the evening before. Anthropic began investigating elevated errors in its Microsoft 365 connector at 17:52 UK time on Thursday, after requests for mail, SharePoint, Teams chat and calendar began failing and new connections could not complete. By 18:34 it had identified an upstream provider as the source. By 22:23 it said the problem was caused by a Microsoft 365 service incident, and that mail, calendar and search tools in the connector were still failing for most requests. Claude for Outlook was also affected, with mail and calendar actions failing and some users unable to open the add-in. That matches Microsoft's own outage. Reports said Outlook, Teams, SharePoint and Copilot were disrupted worldwide from around midday US Eastern time on Thursday, with more than 130,000 Downdetector reports for Outlook alone. Microsoft said the cause was infrastructure, with a number of servers unexpectedly unavailable and straining the rest, and that there was no sign of malicious activity. It reported partial recovery on Thursday evening and the disruption ran into Friday. In plain terms, the connector is down because the thing it connects to is down. [Claude AI Suffers Widespread Outage Across All Its Models on August 18](https://startupfortune.com/claude-ai-suffers-widespread-outage-across-all-its-models-on-august-18/) Claude went down across every major model on August 18, with Downdetector logging more than 4,000 user reports within an hour and Anthropic's status page offering no root cause. The outage is the latest in a run of at least seven incidents over the prior six days, hitting Claude Chat, the mobile app and Claude Code. - [claude AI outage August 18 all models down](https://startupfortune.com/claude-ai-suffers-widespread-outage-across-all-its-models-on-august-18/) - [anthropic status page confirms widespread Claude errors today](https://startupfortune.com/claude-ai-suffers-widespread-outage-across-all-its-models-on-august-18/) ## Our take Two separate incidents on one product make it look like one big failure, and they are not the same. The connector outage is a reminder that an AI tool that reaches into your email and calendar inherits the reliability of every service behind it. The login outage is the more serious one for Anthropic, because it removes access to the product itself. The practical lesson is for any team that has built its daily work on one AI provider. Decide now what you do when it is unavailable: who can switch to another tool, which work can wait, and where your prompts and context live so that you can move them. A few hours of downtime is an inconvenience if you have a fallback, and a stalled day if you do not. We will update this report when Anthropic posts a resolution. Times are UK time. *This article is posted in [News News](https://startupfortune.com/category/news/), check it out for more related stories.* ## Join the discussion [Open in the community →](https://startupfortune.com/community/) Almost there. Sign in and your reply posts straight away.