Microsoft investigates causes of Europe-wide Office 365 outage

Friday email outage for Microsoft Office 365 users

Microsoft's cloud-based Office 365 service has been suffering from widespread downtime across Europe today - and not for the first time in recent months.

The issue affected delivery and receipt of emails, but also made it difficult to conduct searches and retrieve emails in in-boxes.

Down Detector indicates that the borkage is affecting Office 365 users across Europe, in particular, those in the UK.

"All of our locations in UK are down. The other offices in US and Asia are not open yet or have already closed luckily," one Office 365 user moaned

Another complained online: "Get it sorted - not been able to access account at all and working from home. Losing business here!"

Users attempting to access Office 365 email are reportedly being greeted with an 'AADSTS90033' error message, alongside the unhelpful warning: "Service is temporarily unavailable. Please retry later."

The AADSTS90033 error message is typically displayed under normal circumstances when a user cannot get a token from Azure for the services they need to access.

Microsoft has yet to return our request for comment, but has warned IT departments: "We're analysing diagnostic data to isolate the root cause and identify steps to remediate the issue.

"This issue could potentially affect any of your users if they are routed through the affected infrastructure."

Commenting on the outage, Pete Banham, cyber resilience expert at Mimecast, said: "Microsoft Office 365 was hit with major downtime on Friday, with customers around the world unable to access their services or admin portals.

"An operational dependency on the Microsoft environment creates business risks that need be addressed. Anyone outsourcing a critical service like email needs to consider who will suffer most from reputational damage, internal operational issues and financial loss.

"Mimecast is urging organisations to consider a cyber resilience strategy that assures the ability to recover and continue with business as usual."

Computing will update this story as new information comes in.