What is causing the Microsoft outage? Key problem at centre of tech collapse identified by expert

Detailed summary

Millions of people around the globe are impacted by email and other problems

The Microsoft outage which has hit millions of people around the world was caused by “overloaded servers,” say tech experts.

The computer and software giant has said that the problem, still causing major problems on Friday morning, was down to “elevated load”.

Alan Woodward, Professor of Cybersecurity at Surrey University, said: “It’s chaos.

“If I were a betting man I reckon it’ll be a cascade failure to do with the health check, some configuration change internally that triggered it, and progressive inability of other servers to cope with the extra load i.e. a cascading failure.”

James Ferryman, Professor of Computer Science at Reading University, went into more detail, explaining: “The problem is in Exchange Online, which is the email and calendar system behind Outlook. Teams and Copilot rely on it too, for calendars, meetings and getting at people’s work data.

He added: “What Microsoft has told us is that the part of its servers that sets up secure connections is getting swamped, and once that happens the server just stops answering.

“One server falls over, its work gets passed to the next one, and meanwhile huge numbers of phones and laptops keep trying to get back in. You can’t just turn it all back on at once.”

Earlier, Bob O'Donnell, founder of TECHnalysis Research, explained how the elevated load would have led to "overloaded servers".

"A Microsoft exec posted on social media...’It is not cyber. It's not malicious’. It's simply they've overloaded these servers,” he told the BBC.

Opening of the article, excerpted from Evening Standard. To read the rest, open the article on the publisher's site.