Outage in Resend
Deliverability Issues to Outlook Emails
Resolved Minor
March 17, 2026 - Started about 1 month ago
- Lasted about 23 hours
Incident Report
Summary AI Generated
Resend experienced deliverability issues affecting emails sent to Microsoft-owned domains (Outlook.com, Hotmail.com, etc.), causing delivery delays particularly in the eu-west-1 region. The incident lasted 22.7 hours while Resend worked with Microsoft to resolve the underlying delivery problems. Email delivery to Microsoft domains returned to normal timing after the resolution.
We are currently investigating an issue affecting deliverability to Microsoft inbox providers. At this time, some emails sent to Outlook.com, Hotmail.com, and other Microsoft-owned domains may experience delivery delays.
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Latest Updates ( sorted recent to last )
MONITORING
about 1 month ago - at 03/18/2026 08:53AM
We’re seeing delivery to Outlook.com, Hotmail.com, and other Microsoft-owned domains return to normal. Emails are now being delivered in a timely manner. We’ll continue to monitor closely.
IDENTIFIED
about 1 month ago - at 03/18/2026 12:32AM
We’ve identified that this issue is impacting domains in the eu-west-1 region. We’re actively escalating with Microsoft to resolve this as quickly as possible. Please reach out to support@resend.com for any questions and concerns.
IDENTIFIED
about 1 month ago - at 03/17/2026 03:58PM
We've identified that Microsoft addresses (outlook.com, hotmail.com, and other Microsoft-owned domains) are experiencing delivery delays at an elevated rate.
We've informed Microsoft and are monitoring.
INVESTIGATING
about 1 month ago - at 03/17/2026 03:47PM
We are currently investigating an issue affecting deliverability to Microsoft inbox providers. At this time, some emails sent to Outlook.com, Hotmail.com, and other Microsoft-owned domains may experience delivery delays.
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