Who is affected?

Users who are using Outlook to connect to Office 365 for email

Problem:

Connection problems with Office 365

Systems Involved:

Office 365

Details:

Some users may not be able to send or receive mail using Outlook.  This problem does not appear to affect all users.  Microsoft is aware of the situation and is investigating.

Users who are having problems connecting with Outlook can still use OWA as that does not appear to be affected.

Updates:

7/15/2015 5:14:39 PM:
Current Status: [Microsoft] Engineers have determined that this issue may be related to a recent update to the service and are currently working to revert the update.

7/15/2015 4:41:21 PM:
From Microsoft: Current Status: 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.

User Experience: 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).

Customer Impact: A higher than average number of customers are reporting this issue. Analysis indicates that customers will likely have some users experiencing this issue.

7/15/2015 4:05:12 PM:
Microsoft has stated the problem has expanded and now impacts users on OWA as well as mobile devices in addition to Outlook clients.�

7/15/2015 3:50:20 PM:
7/15/15 - 3:48pm - the problem is also affecting the transport servers, so email delivery for all users is also impacted.

Problem Resolution: 

Microsoft has fixed the problem.  The mail that was backlogged during the outage has been delivered.