This issue has been resolved.
Update, 2:42 p.m. — This issue has been resolved. Microsoft 365 services and OWA are now back to normal operation. We apologize for any inconvenience this may have caused. If you’re still experiencing issues with this service, please contact the IT Support Center at (310) 825-8000 or firstname.lastname@example.org.
Update, 2:10 p.m. — Access has been restored for some users. We’ll send out another update when we have more information from Microsoft. Thanks for your patience.
We’re getting reports that some Outlook and Office 365 users may be experiencing issues with logging into OWA and Microsoft 365 services. Affected users are unable to authenticate to and access Microsoft 365 services. Microsoft has identified a degraded portion of infrastructure that manages authentication requests and have restarted that infrastructure to mitigate impact. We're investigating the issue, and working with Microsoft to fix the problem. We will update when we know more.