The investigation determined that a portion of infrastructure which facilitates authentication to the service is experiencing higher-than-normal resource usage. Engineers are analyzing service telemetry to determine what is causing the high resource usage.
Affected users are unable to connect to the Exchange Online service when using multiple protocols including Outlook, Outlook Web App (OWA), Exchange ActiveSync (EAS), and Exchange Web Services (EWS).
We will post another announcement when we have more information from Microsoft.
Should you have any questions, please contact the Campus Support Center at 479-968-0646.