Maintaining External Email Flow During a Microsoft 365 Outage

As rare as it is – many Microsoft customers, including WTG, recently experienced a degraded service condition in Microsoft 365 on Thursday, January 22.  For over nine hours, those impacted experienced issues including significant external email delivery issues/delays to Microsoft 365.

Here at WTG, we use Mimecast as an email gateway and, because of that, external email continued to function. We were able to instruct users to switch to the Mimecast inbox (either Personal Portal or Outlook Plug-In) and send and receive external messages using Mimecast’s infrastructure. That capability exists because Mimecast operates as a gateway in front of Microsoft, not as a feature that depends on Microsoft being fully available.

Inbound external email continued to be accepted and stored by Mimecast while Microsoft services were degraded. Outbound external email could also be sent through Mimecast, which meant conversations with customers, partners, and vendors continued without waiting on Microsoft to recover. Once Microsoft service stabilized, normal mail flow resumed and inbound messages were delivered into Microsoft 365 as expected.

This incident highlighted one specific capability, but it is only a small part of why organizations deploy Mimecast (we like to think of Mimecast as a “Swiss Army Knife” of email management and security). The same gateway architecture that enables continuity is also what underpins Mimecast’s security, archiving, and email management features. It is one platform handling multiple email problems in one place, rather than a collection of narrow tools tied directly to M365’s availability.

The value is having one platform that keeps email flowing, protected, and manageable, even when your cloud-hosted email provider is having issues.