Microsoft Teams, the software giant's collaboration platform for work, has over 20 million daily active users and is one of the biggest Slack competitors. It bundles chat, video conferencing, file storage, and app integration tools into a single platform. However, Microsoft Teams users experienced a brief outage earlier today that kept them from signing in to their respective teams. But the reason behind the service outage was a pretty embarrassing one. In Microsoft's own words, the company forgot to renew a security certificate for its collaboration platform, which resulted in an HTTPS error for users trying to sign in.

Responding to reports of users unable to access Microsoft Teams, the official Microsoft 365 Status Twitter handle shared that "an authentication certificate has expired." An hour later, the team announced that it has started deploying the updated certificate for Microsoft Teams service. And roughly after five hours, Microsoft notified affected users that the fix has been deployed to resolve the log-in issue, and that additional remedial actions have been conducted to address the glitch.

Needless to say, Microsoft Teams users were not very happy with the disruption, especially after learning that the issue was caused by an embarrassing blunder. But it appears that the company has learnt the lesson. Microsoft further noted that it is reviewing its certification deployment and provisioning steps to make sure that such service outage incidents are not repeated in the future.

However, this is not the first time that a Microsoft service has experienced widespread disruption due to certificate expiration. Back in 2013, Microsoft Azure was hit by a global outage, thanks to the expiration of an SSL (Secure Sockets Layer) certificate. The mistake affected HTTPS operations on a large scale. On the same day, Microsoft reported issues with Xbox Music and Video services as well.