Microsoft 365 suffered a significant outage on 23 July, leaving many businesses unable to access Teams, SharePoint, Excel Online and the admin centre for several hours.

• What happened: A bug in Microsoft's own automated network maintenance system removed IP routing for more devices than intended, disrupting Azure and Microsoft 365 services.
• Who was affected: Users of Teams, SharePoint Online, OneDrive, Excel and the Microsoft 365 Admin Center reported errors and lost access, with SharePoint the hardest hit at 78% of reported complaints.
• The risk: No data was lost, but businesses relying solely on Microsoft 365 for communication and file access had no fallback while services were down.
• What to do: Microsoft reverted the faulty update and services were restored the same day. It is a timely reminder to have a backup way to reach staff and clients, such as mobile numbers or a second messaging app, if your main systems go down.

We recommend checking the Microsoft 365 Service Health dashboard during any unexplained outage so you know whether it is a Microsoft-side issue before troubleshooting locally.

Source: BleepingComputer.