Microsoft's Outlook service is down worldwide and the outage is affecting the service across the web as well as its apps on mobile and desktop. The outage was first reported around 2AM ET, with Microsoft confirming the issues. Due to the outage, Microsoft Outlook users are unable to access Outlook.com and are unable to use its desktop or mobile app to check their emails.
We’ve collected additional data from the affected infrastructures to determine impact to our Exchange online protocols. Additionally, we’ve identified this issue to be affecting users worldwide. Further details can be found in your admin center under EX223208.— Microsoft 365 Status (@MSFT365Status) October 1, 2020
Microsoft says that it is "reviewing recent changes" to its services to determine the cause of this outage. It also notes that users with Exchange Online protocols may also face some service issues. Many users are also reporting issues while trying to use Microsoft Teams, though the company has not acknowledged any service issues with it. DownDetector also shows that Microsoft Teams is having a service outage right now.
This Outlook service outage comes within days of another major Microsoft outage that saw Outlook, Office 365, Teams, OneDrive, and other services being down for more than five hours worldwide.
Update: The issue has now been resolved by Microsoft. It was caused by a recent configuration update.