Title: Issue affecting viewing email content in Outlook

User Impact: Users may be unable to view email message content within Outlook.

More info: Impact is specific to the Outlook client and users with access to other protocols, such as Outlook on the web or the Outlook mobile app, can view message content in those platforms as a potential workaround while our fix is applied.

Current status: We’ve identified the underlying cause of impact and are applying a fix. This fix will reach all affected users incrementally over the course of the next four-to-five hours. Once users receive the fix, they will need to restart their email client to apply the fix. In some circumstances, users may need to restart their client a second time for the changes to take effect. We expect to complete this process and restore service for all affected users by May 12, 2021, at 3:00 AM UTC.

Scope of impact: This issue could affect any user attempting to view an email message in the Outlook client.

Root cause: A recent change to systems that facilitate text display management for content within the Outlook client caused impact.

Microsoft's Error Code: EX255650
Issue Start Time: May 11, 2021 1:54 PM
Status Updates Can Be Found Here