Microsoft Exchange Online is experiencing an outage that mainly affects European users. Users have been experiencing delays in sending and receiving emails since around 12:30 p.m. Central European Summer Time.
Several users have reported experiencing problems, although the exact extent of the issue is still unclear. Microsoft acknowledges the problems on a support page in the closed admin center. The company states that “some users located in Europe” may experience problems sending or receiving emails via Exchange Online.
The tech giant has identified the cause of the problem. It involves “an abundance of service-to-service calls” that are causing authentication issues. Microsoft is trying to resolve the problem by limiting such calls, but has not yet announced a definitive solution.
Broader context
This outage affects the email service used by millions of business users for daily communication. Users who rely on Exchange Online for business communication should expect ongoing delays. Microsoft is working on a solution but has not provided a timeframe for full service restoration.
This is far from the first outage affecting Microsoft services this year, from Outlook problems to Teams outages or complete 365 outages. The question is whether Microsoft can identify a pattern here, but as the second-largest cloud player and by far the most popular software provider, even a minor problem can quickly affect hundreds of thousands of users or more.