No, you were not alone! Microsoft Teams and several other Microsoft 365 apps went down on the night of Wednesday July 20, causing frustration for many people. Although the issue has been resolved, Microsoft has since updated customers on what went wrong on their end to cause all of these issues (via ZDNet.)
According to a tweet from the Microsoft 365 Status account, it appears that Microsoft messed up a recent rollout and had a dropped connection to an internal storage service, which impacted services. Microsoft then fixed this issue by directing traffic to a healthy service to mitigate the impact. Teams, Exchange Online, Microsoft Word, Forms, Graph API, Office Online, SharePoint, Project Online, Power Platform and PowerAutomate, Yammer, and Windows 365 have all been impacted because of this.
We determined that a recent deployment contained a broken connection to an internal storage service, which had an impact. We are working to direct traffic to a healthy service to mitigate the impact. Additional information can be found in the admin center under TM402718.
— Microsoft 365 Status (@MSFT365Status) July 21, 2022
Initial reports of issues began around 9:47 p.m. ET on July 20, and the issue was resolved for most people by 2:15 a.m. ET on July 21. Some users are still reporting issues with Teams on the morning of July 21, however. The Microsoft 365 admin center still lists reviews for Microsoft Teams and these other apps. Microsoft says service availability in all regions remains above 99% and will monitor the application of targeted mitigations for residual impacts.