9/5/18: Microsoft has removed the issue and is reporting that the problems should be fixed.
Users may be unable to access or use some features within the Office 365 service. We’ve determined that a data center issue caused a subset of the Office 365 service to become degraded. We’re connecting some of the affected services to an alternate infrastructure, while remediating the underlying issue within the data center. Impact is specific to a subset of users who are served through the affected infrastructure.