Microsoft 365 outage left Bing ads running but reduced Outlook ad requests

Ads kept serving during the outage

A major Microsoft 365 outage that began on 12 November 2026 disrupted services such as Exchange Online, the cloud email system many businesses use. According to Search Engine Roundtable, the problems did not directly affect Microsoft Advertising or the adverts shown in Bing Search.

Navah Hopkins, the Microsoft Ads Liaison, addressed the topic on LinkedIn. She explained that advertisers should not worry about adverts failing to deliver, but that the incident could still have a financial effect on some campaigns.

What Microsoft says about the cause

Microsoft confirmed the trouble on X on 12 November, saying users in the Americas could not reach Exchange Online mailboxes through several connection methods. The company referenced incident EX1550543 in the Microsoft 365 admin centre.

In a statement reported by Search Engine Roundtable, Microsoft said the fault came from an earlier network capacity upgrade that surfaced after a recent network change. The company stressed it was not related to cyberattacks or to AI agents, and that it had fixed the underlying issue while gradually restoring services region by region.

Microsoft said the slow, staged recovery was deliberate. Engineers validated stability at each step before moving on. A full post-incident report is promised once the review is complete.

Why advertisers may still see changes

Because many people could not load Outlook during the disruption, the number of incoming ad requests in that product dropped. Microsoft acknowledges this may affect spend for some advertisers, since fewer requests means fewer chances for adverts to be shown.

The company apologised for the inconvenience on LinkedIn and on its status page. Its advertising status page states that the health of the Microsoft Advertising platforms and their delivery was not harmed by the wider service disruption.

Status and what to do next

The incident began around 7:15 AM Eastern Time on 12 November, according to the advertising status page. As of the afternoon of 13 November, Microsoft said recovery was broad but not fully complete, roughly 24 hours after the first reports.

Microsoft Advertising says it will close its own advisory once the broader Microsoft 365 recovery is confirmed. Advertisers can check the official status pages, status.ads.microsoft.com and status.cloud.microsoft, for the latest updates. Anyone with questions about campaign spend was invited to contact the advertising team for help.