Microsoft 365 Outage Enters Second Day, Hitting Teams, Copilot and Claude

Microsoft's global Outlook outage ran into a second day on Friday, leaving businesses without email and disrupting Teams, Copilot, SharePoint and — notably for marketing and AI teams — the Microsoft 365 connectors that power Claude and OpenAI's tools.

The outage is not contained to email. In its service advisory, Microsoft said the disruption could affect Outlook, Teams, SharePoint, Copilot, Microsoft Defender, Intune, Power BI and other Microsoft 365 products that rely on Exchange Online. For CMOs, that means campaign coordination, shared documents and AI-assisted workflows built on the Microsoft stack were all exposed at once.

Anthropic and OpenAI both reported on their status pages that their connectors to Microsoft 365 tools were disrupted. Anthropic added that authentication issues were affecting Claude Code, though it did not attribute that problem to the Microsoft outage.

What is the latest status?

Microsoft said in a 6:11 a.m. ET update on Friday that it had made "additional progress toward recovery," with some mailbox access restored and delayed email processing improving. But it warned users could still face intermittent issues, and the company has given no timeline for full recovery.

The mechanics of the failure are infrastructure, not demand. Microsoft said in a Thursday X update that some of its infrastructure was under elevated load across multiple regions. The strain was not caused by a rise in customer traffic; a number of servers had unexpectedly become unavailable.

Microsoft said in a 3:34 a.m. update that it had "no indication" the disruption was caused by malicious activity. It has taken steps including restarting servers. Early Friday, the company said servers that initially returned to service could become unresponsive again once traffic reached them.

How big is the impact?

Downdetector recorded more than 130,000 reports of Outlook problems in the US at the outage's peak on Thursday. That figure counts user reports, not a confirmed number of affected people or businesses. Either way, the scale ranks among the largest Microsoft 365 disruptions to date.

The blast radius spans governments and corporates:

• The US House of Representatives said the outage affected its users, Reuters reported.
• Electric-truck maker Workhorse Group postponed its quarterly earnings call because of the disruption.
• Air India said in a Thursday X post that it had rerouted email services; IndiGo said Friday its email support channel was disrupted. Both airlines confirmed flight operations were unaffected.
• Government agencies in Singapore, the Philippines and Japan reported knock-on effects, according to AP.

What does this change for marketing leaders?

The episode exposes a concentration risk that few marketing orgs have planned for. When Exchange Online fails, email, Teams collaboration, SharePoint assets, Power BI dashboards and AI assistants such as Copilot and Claude's Microsoft connector fail together — a single dependency, not separate systems. Anthropic's disclosure that Claude's Microsoft 365 connectors were hit shows how quickly AI workflows inherit the fragility of their underlying platforms.

Microsoft first flagged the problem around midday ET Thursday in an X post, saying users in the Americas were having trouble accessing Exchange Online mailboxes. A follow-up post said the issue could affect users "in any region." By Friday morning, the public service status page still showed "service degradation" for both Microsoft 365 business customers and consumer products.

No recovery timeline exists. Teams that ran Thursday's campaigns on Microsoft infrastructure should plan for a third day without guaranteed service.