Microsoft says an Exchange Online issue that mistakenly quarantined legitimate emails last week was triggered by faulty heuristic detection rules designed to block credential phishing campaigns.

Microsoft confirms Exchange Online and Teams messages were mistakenly quarantined due to a phishing detection bug (EX1227432).

Microsoft 365 January updates add Teams drafts and time zone sync, helping you reply faster and keep chats consistent across devices.

Microsoft is shifting its stance on workplace collaboration from “optional safety” to “secure by default.” Beginning Jan. 12, 2026, the tech giant will automatically flip the switch on a trio of ...