Resolved after 1 day, affecting Email sending (SMTP service) and API Servers, on February 26, 2026.
We are currently aware of a global issue affecting emails sent to Microsoft-hosted domains (such as hotmail.com, outlook.com, live.com, etc.). Emails affected will show as "Processed" on the "Reports > Activity" page, and delivery attempts encounter "451 4.7.650……….." responses. This is a Microsoft-wide issue affecting multiple SMTP providers/ESPs, and we are monitoring it closely as they actively work on a fix. Thanks for your patience.
Affected components
Update timeline
- monitoring Feb 26, 2026, 03:01 AM UTC
We are currently aware of a global issue affecting emails sent to Microsoft-hosted domains (such as hotmail.com, outlook.com, live.com, etc.). Emails affected will show as "Processed" on the "Reports > Activity" page, and delivery attempts encounter "451 4.7.650……….." responses. This is a Microsoft-wide issue affecting multiple SMTP providers/ESPs, and we are monitoring it closely as they actively work on a fix. Thanks for your patience.
- resolved Feb 27, 2026, 03:08 AM UTC
This incident has been resolved.
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