Microsoft is scaling down non-essential Office 365 capabilities in response to incoming growth in demand and the influx of new Microsoft 365 users caused by the novel coronavirus (COVID-19) pandemic. Microsoft will tweak these temporary feature adjustments as the current situation changes and the Microsoft 365 servers’ load will wind down as users move away from remote working from home. Microsoft Teams outage affected EU and some US users between March 16 and March 17, with reports saying that messages in chat weren’t being sent, team member management not working, and the admin portal being unreliable.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-scales-back-office-365-features-to-handle-high-loads/