Inc. noted on Thursday that Anthropic and OpenAI experienced connection failures preventing ChatGPT and Claude access Microsoft 365, following a Microsoft service disruption that blocked millions from using Teams, Outlook, and other applications.
ChatGPT has separate plugins for Outlook email and calendar. Claude connects to both through a single Microsoft 365 connector that can also pull in Teams chats and SharePoint files.
OpenAI warned that new Microsoft connections with ChatGPT could fail and that its “tools are not working as expected.” Anthropic said that most requests on Claude to its mail, calendar, and search tools were failing.
Some users could not even open the separate Claude add-in that runs inside Outlook, according to the same report.
By late Friday morning, both companies reported signs of recovery. However, Anthropic said that some SharePoint searches were still returning errors.
Neither AI lab disclosed how many users were affected by the disruption.
Functioning integrations allow AI assistants to check a calendar, draft a response, extract action items, and summarize email conversations. Conversely, when these features break, dependent entrepreneurs must manually arrange meetings, track down supplier delivery dates, and search through their inbox ahead of client discussions.
The Microsoft outage unfolded as fears swirled about how AI agents could be deployed in cyberattacks. Microsoft wrote on X that there were no signs that malicious activity caused the disruption, demonstrating how quickly work piles up when several tools rely on the same service.
