Microsoft is looking into a service outage that is affecting Exchange Online users who are having trouble getting to their mailboxes through one or more connection methods. The problem, which is being tracked on Microsoft 365's service health dashboard, has led to several status updates on Monday, March 16, 2026. Reports started coming in earlier on Monday, and Microsoft made its first official statement at 4:26 PM IST.
At 4:53 PM and 7:49 PM IST, the company sent out more updates, showing that its engineering teams are hard at work figuring out what went wrong and getting the service back to full functionality. The incident has an effect on Exchange Online, Microsoft's cloud-based email and calendar service that serves millions of business and enterprise customers around the world.
Clients like Microsoft Outlook (desktop and mobile), Outlook on the Web (OWA), and possibly third-party email clients that depend on protocols like MAPI, IMAP, or EWS may not be able to connect to affected users' mailboxes. The advisory's description of the impact's scope, which includes one or more connection methods, implies that not all access pathways are equally impacted. Although Microsoft has not yet made public the precise number of impacted tenants or the geographical areas involved, the disruption seems to affect a portion of Exchange Online users.
Businesses that use Exchange Online extensively for daily communications, such as calendar scheduling, email workflows, and shared mailbox access, may encounter sporadic or continuous connectivity issues during this time.
What Microsoft Said The engineering team is working to fix the problems with Microsoft's 365 service health portal, which has been updated several times. Users and IT admins should check the Service Health section of the Microsoft 365 admin center for real-time updates. As the investigation goes on, the company has promised to give more updates.
As a temporary fix, administrators might tell users to switch to a different way of accessing the service that isn't affected, like switching from a desktop client to Outlook on the Web or the other way around, depending on which connection method is having problems in their environment.
Advice for IT Managers For the most recent incident updates, go to the Microsoft 365 admin center and look under Health > Service Health. Find out which specific connection methods are affected in your tenant. To cut down on the number of helpdesk tickets, make sure end users know what the status of the service is.
Think about using unaffected access methods as temporary workarounds. Keep track of the effects of documents on SLA or compliance records within the company. Microsoft hasn't said what caused the problems yet, but they could be due to a change in infrastructure, a deployment update, or a configuration issue. As the investigation goes on, more technical information is expected to be released in future updates., LinkedIn, and X for daily news about cybersecurity.
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