Global Microsoft 365 outage disrupts email and Teams for over nine hours

Millions of users worldwide, including Irish businesses and public bodies, were unable to access Microsoft 365 services from Thursday evening until early Friday morning.

At about 6 pm Irish time on Thursday, the outage‑monitoring site Down Detector recorded a sharp rise in reports of problems with Microsoft 365, the cloud suite that includes Outlook, Teams, Word, Excel and PowerPoint. The disruption lasted more than nine hours, affecting email, Teams chats and meetings.

Microsoft said the issue stemmed from a configuration update that overloaded some servers, causing them to go offline. When engineers attempted to restore the servers, traffic surged back, making the servers unresponsive again. The company limited traffic to affected servers and rolled back to an earlier software configuration on some machines.

By 2 am Irish time on Friday, most problems were traced to Microsoft Exchange, the email service behind Outlook, and Teams functionality had been restored. Irish councils, state and federal agencies, courts and schools reported they could not be contacted by email on Friday morning, while businesses and healthcare providers said their own services remained operational.

Microsoft dismissed speculation that the outage was a cyber‑attack, stating there was no evidence of such activity. The incident highlights the growing reliance on cloud‑based software and the need for organisations to test updates thoroughly and maintain backup options.

Impact on Irish public services

Several Irish county councils and government departments confirmed the outage hampered routine communications, prompting reminders about the importance of contingency plans for critical digital services.

Source: Irish Examiner. Photo: Brett Sayles / Pexels.