Microsoft said it is working to resolve an hourslong outage that has disrupted services that include Outlook and Teams, with government departments and schools from the U.S. to Australia among those affected.Microsoft first said it was investigating reports of problems encountered by users attempting to access their email at 1254 ET on Thursday.A company spokesperson said Microsoft was working to address issues affecting Microsoft 365 services, such as AI software Copilot, and restore services as quickly as possible.“We have no indication of a cyber attack,” the spokesperson added.However, initial efforts hadn’t been as successful as hoped.The company said on X that changes made to improve serviceability aren’t taking as expected. It is seeking ways to boost capacity to allow more information to flow while attempting a fix to the system.“We’re observing partial recovery across regions in which we’ve applied these adjustments,” Microsoft said on X. “However, these actions aren’t resulting in sustained recovery, so we’re reviewing what additional actions we can take.”Microsoft first said it was investigating reports of problems encountered by users attempting to access their email at 1254 ET on Thursday.According to outage tracker Downdetector, tens of thousands of users have reported problems accessing Microsoft’s email and online-meetings platform.Users visiting some government websites, including in the U.S., were met with appeals for them to contact offices by phone.

In Australia’s remote Northern Territory, where many classes are held online, education officials said schools were experiencing technical difficulties and urged people to be patient.OpenAI said its ChatGPT service was affected and it was working to mitigate the impact. Anthropic flagged a similar issue that is affecting its Microsoft 365 connector and Claude for Outlook.“We’re investigating an issue with Microsoft connectors where new connections may be broken and tools are not working as expected,” OpenAI said on its website.The Microsoft outage mirrors problems that hit Cloudflare and Amazon Web Services a year ago, roiling the systems that individuals and businesses use to communicate with each other.

The Cloudflare outage in November 2025 knocked swaths of the internet offline, including social-media sites.Experts said the latest outage is a reminder of the dangers that businesses face when relying on one service for vital communications. It also highlights the importance of contingency planning.“Customers need a rehearsed plan for keeping essential work and communications going when their usual services are unavailable,” said Mohammad Goudarzi from the faculty of information technology at Australia’s Monash University.As of 0030 ET Friday, many of Microsoft’s services remained down.

The company’s health status website showed “service degradation.”Write to Kimberley Kao at kimberley.kao@wsj.com and Fabiana Negrin Ochoa at fabiana.negrinochoa@wsj.com