Hotmail and Outlook.com have been affected by a major outage that blocked users from accessing their accounts in many countries around the world for approximately 16 hours.
It appears that the problem was caused by datacenter overheating that triggered the servers’ safeguards to come into place and disconnect a large number of systems.
“These safeguards prevented access to mailboxes housed on these servers and also prevented any other pieces of our infrastructure to automatically failover and allow continued access. This area of the datacenter houses parts of the Hotmail.com, Outlook.com, and SkyDrive infrastructure, and so some people trying to access those services were impacted,” Microsoft explained
Microsoft doesn’t reveal the number of affected accounts, but it claims that access was restored by 5.30 AM. At this point, both Outlook.com and Hotmail are working just fine.