Microsoft 365 Alert : Service Degradation – Exchange Online – Some users may be intermittently unable to access Outlook on the web – RESOLVED

01/06/2022 08:29:00 AM (BST)

Microsoft Reference : EX387031  

Issue Status : RESOLVED

Issue Description : Users may be intermittently unable to access Outlook on the web.

More info : Some users may be able to access Outlook on the web but are unable to access various features. In addition to the Outlook on the web impact, admins may be intermittently unable to access the admin center.

Scope of impact : This issue may have impacted some of your users that were attempting to access Outlook on the web. Some of your admins trying to access the admin center may have also been affected.

Final Update : 02/06/2022 08:29:00 AM – Further investigation determined that a misconfiguration in Microsoft’s third party provider for Content Delivery Network (CDN) services was preventing user traffic from accessing service infrastructure. After working with their third party provider, Microsoft have verified that the misconfiguration has been corrected and confirmed with some affected users that impact is remediated.

Root cause : A misconfiguration in Microsoft’s third party provider for Content Delivery Network (CDN) services was preventing user traffic from accessing service infrastructure.

Next steps : Microsoft are reviewing the affected infrastructure to better understand how impact began, which will allow them to prevent similar impact in the future.