Microsoft's Outlook email service and other Microsoft 365 products were down for tens of thousands of people on Thursday afternoon, with outage reports surging after midday Eastern time.
Outage tracker Downdetector recorded a sharp spike in reports about Microsoft 365 services beginning just after 12 p.m. ET, with 22,323 users reporting outages by 12:55 p.m. ET. Reports for Outlook alone reached just short of 83,000 just before 1 p.m. ET, while about 2,000 users reported problems with Teams and 4,400 reported issues with Copilot around the same time.
Microsoft said it was investigating reports of users having trouble accessing Exchange Online mailboxes through multiple connection methods in the Americas. The company assigned the incident the reference number EX1550543 and directed administrators to the Microsoft 365 admin center for updates.
The company said it had identified connection errors in the part of its Exchange Online infrastructure that receives and processes requests for access to user mailboxes. The cause of the outage had not yet been disclosed.
Earlier on Thursday, Microsoft reported a separate problem with Teams functionality in North America at 10:40 a.m. ET, but said in the same thread that it had been resolved around noon. Users in Britain also reported problems, with more than 5,000 reports on Downdetector by 5:40 p.m. local time and many seeing a "Failed to fetch" error when trying to load Outlook.
