A worldwide Microsoft Teams outage is blocking users from logging into their accounts, and preventing those already logged in from sending and receiving messages. Microsoft is already seeing signs of recovery and advises users still experiencing issues to restart their clients. The outage impacted customers between 9:58 AM UTC UTC and 12:05 PM UTC. Microsoft says all Teams features are now working as expected and will continue to monitor the service. Earlier this month, Azure DNS servers overloaded by an “anomalous surge”” of DNS queries from all over the world caused a global outage.”
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-teams-worldwide-outage-impacts-user-logins-chats/