A Microsoft 365 outage affects Outlook, Teams and Copilot, and the connectors for ChatGPT and Claude
IA en un minuto newsroom · Editor: Jon Elgezabal
In 30 seconds
Outlook, Teams and Copilot stopped working properly on Thursday because of a failure in Microsoft 365 servers. ChatGPT and Claude felt it too, since their connectors to that work data began returning errors. Microsoft said the problem could reach any region, and for some users it stretched past the five-hour mark.
Microsoft 365, Microsoft's bundle of work apps, went down on Thursday, November 12, leaving many users unable to open their Outlook email and also hitting Teams, its messaging service, and Copilot, its AI assistant. The failure also reached ChatGPT and Claude through their connectors with Microsoft 365.
In its posts on X, Microsoft explained that several servers had crashed unexpectedly and that this overloaded the rest of its infrastructure, and it warned that connections could fail for users in any region. It also admitted that its first measures had not worked. According to Open Magazine, the company was undoing a recent change to the configuration of its network that began at the same time as the problem, and a spokesperson told The Guardian, as reported by the same outlet, that they had seen no signs of a cyberattack.
The service that failed most was Exchange Online, which keeps companies' email and calendars and delivers their messages. That is why chats and meetings in Teams largely kept working while the calendar and meeting scheduling did not, and Copilot could fail to load or to reach work email, calendars and files, according to the Microsoft status page quoted by Goodreturns. On Downdetector, the site that gathers the outage reports sent by users, complaints about Outlook reached about 138,000 around 1 p.m. US Eastern time, according to Open Magazine. For some users the problem went on for more than five hours, and early on Friday in India Microsoft had still not confirmed that the service had fully recovered.
OpenAI and Anthropic, whose assistants can get into a user's Microsoft 365 work data with permission, warned of failures through that route. OpenAI explained that the problem with its Microsoft connectors could block new connections and stop some tools from working properly. Anthropic blamed it directly on the Microsoft incident: its Microsoft 365 connector was failing on most mail, calendar and search requests, and Claude for Outlook was still affected.
Why it matters · analysis and opinion
The more AI assistants plug into a company's email and calendar, the more services depend on a single provider, and this outage made that plain: a failure in Microsoft's servers left tools from other companies half working. For anyone who works with ChatGPT or Claude connected to Microsoft 365, the consequence is practical: when email goes down, everything that relies on it goes down too. Having another way ready to reach clients and teams, one that does not depend on the same service, limits the damage of a day like this. It remains to be seen what triggered the failure and whether the network change Microsoft was undoing had anything to do with it, something the company has not yet explained.
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What does it mean for your business? · analysis and opinion
This affects any business, shop or freelancer in Spain and Latin America that uses Microsoft 365 email, calendar or Teams. And above all, anyone who has connected ChatGPT or Claude to those accounts to summarize emails, prepare meetings or search for work information. Microsoft warned that the outage could affect users in any region, so it did not stay within the United States. Anyone using another email provider without connectors to Microsoft was not directly affected.
In practice, it helps to have an alternative channel written down to notify clients and the team when email or Teams does not respond: a phone number, another email account or a messaging group. It also helps to keep what is needed every day, such as the schedule for the week or key contacts, outside Microsoft 365. If a task depends on an AI assistant connected to email or the calendar, it is wise to have a way to do it by hand. None of this costs money, only a bit of organization.
For some users the outage lasted more than five hours, and during that time the connected assistants could not work with email or the calendar either. Our advice is not to leave time-sensitive tasks, such as sending a quote or confirming an appointment, in the hands of a single provider without a backup plan. When the service comes back, it helps to check that no message or appointment is missing.
