Delayed Email Deliverability
Microsoft's Outlook team has confirmed that mitigations have been implemented. We've verified that email delivery to Microsoft 365 domains is operating normally again. This incident has been resolved.
The latest update from WorkOS.
State
Resolved
Started
78 d ago
2026-08-15 01:35 UTC
Lasted
44 h 29 min
until 2026-08-16 22:04 UTC
Worst impact
Degraded
Timeline
5 updatesIdentified
31 h 39 min 71%
Monitoring
12 h 50 min 29%
Updates
Times in UTCAs posted by WorkOS
Microsoft's Outlook team has confirmed that mitigations have been implemented. We've verified that email delivery to Microsoft 365 domains is operating normally again. This incident has been resolved.
We continue to see email deliverability issues to a subset of Microsoft 365 tenant domains. This does not affect consumer domains such as outlook.com, hotmail.com, live.com or msn.com. We will provide updates as they become available.
We are observing improvements in deliverability to Microsoft email addresses, in line with the resolution of an incident with our upstream email service provider. We will continue to monitor.
We continue to experience deliverability delays to a subset of users with email addresses hosted by Microsoft / Office 365. We are working with our email providers to mitigate the issues, we will provide updates as they become available. Customers using their own custom email providers are not affected.
We are seeing deliverability issues with emails sent to Microsoft / Outlook recipients.
Affected components
2WorkOS in the last 90 days
Full historyIncidents in 90 days
17
Days with an incident
17
Median duration
58 min
This incident
46× the median
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