Source: IncidentHub, based on Microsoft service health updates

On October 13, Microsoft 365 users in Germany and the United Kingdom who connect through Global Secure Access (GSA) could not reliably use Outlook, Outlook on the web, OneDrive, SharePoint Online, Microsoft Teams or Windows 365 Cloud PCs. According to Microsoft’s service health updates, the incident window ran from 07:40 to 18:31 UTC, with impact scoped to Germany and the UK until 17:26 UTC and Germany only after that. Microsoft attributed the disruption to a section of GSA infrastructure performing below acceptable performance thresholds. Users connecting to Microsoft 365 without going through GSA were not affected.

The security tooling paradox

GSA is Microsoft’s zero-trust network access product that routes traffic through a secure tunnel before it reaches Microsoft 365. The incident shows the trade-off European organisations make when they concentrate access through a security layer: when that layer degrades, the productivity suite behind it becomes unreachable even though the suite itself is healthy. Businesses in both countries reported that email, file access and collaboration stalled for a large part of the working day.

How to prepare for the next one

Teams that weathered the outage best had break-glass paths documented, status monitoring wired into their incident response process, and clear internal communication lines for telling staff what was happening. If your organisation routes Microsoft 365 through GSA or another zero-trust access layer, it is worth reviewing what your fallback is when the access path fails, not just when the service does.

If you want help designing resilient access architecture, planning fallback connectivity or setting up service health monitoring for your Microsoft estate, contact Excello Digital at https://excello.digital/contact/. We help European businesses stay productive when cloud services misbehave.