Updated Microsoft's Office 365 service has gone offline for many users in the UK and Europe, though the cause and extent of the outage is not yet known.

Neither the Office 365 portal, nor the Azure management portal is available at the time of writing, though Microsoft's status page says everything is fine.

Everything is fine says status page - but users cannot log in

Some users say email is still being received, but the issue may be with Azure Active Directory. If this service is unable to authenticate users, multiple Microsoft cloud services become inaccessible.

One Microsoft Gold partner told us, "the irony is you can't even log a support ticket."

But he quipped that the length of time of the outage - service seems to have been interrupted for a couple of hours - was "ntohing".

"[In past outages we] haven’t been able to access the partner portal resources, downloads and keys for over a month, since our renewal. They say they are working on it. Meanwhile all our computers sport an activation message in Windows 10 and Office 2016 looks great in front of customers."

Another Microsoft partner has contacted us, and said, "most" of the online services for Office 365 are down, local versions of Outlook etc. are still working but are experiencing performance issues. He added iPhone and iPad apps and the web protal login pages are also offline.

"Microsoft are having a bad day," he said.

Update 1

According to Microsoft’s Azure Status Page, the reason for this Azure Active Directory outage was an “Azure Active Directory configuration error” followed by a failover failure.

A status update, now deleted, said that “Prior to executing a failover, the Azure Active Directory team identified an issue with the failover mitigation path, which would have blocked the mitigation.”

Plan B was to revert the Azure Active Directory front ends to call a “known good configuration.” This has now been implemented and the status now reports “a significantly improved experience.” We are now able to log into Office 365 so the service is much improved. The outage was severe for around three and a half hours from 9.00am.

The status reports also confirm the large number of services affected, including Stream Analytics, Remote App, Visual Studio Team Services and SQL Database, in addition to the Office 365 and Azure management portals.

Update 2

A Microsoft spokesman said:

“Some customers, particularly those in Europe and the UK, may have been unable to access services earlier today. Services are fully restored and we thank customers for their patience." ®