Outage in Resend
Delivery Delayed Events to Microsoft Hosted Domains
Resolved Minor
July 20, 2026 - Started 4 days ago
- Lasted 1 day
Incident Report
Summary AI Generated
Resend experienced a ~26-hour incident where emails sent to Microsoft-hosted domains (Outlook, Hotmail, etc.) were delayed in delivery. Resend worked directly with Microsoft to identify and resolve the root cause. Microsoft addressed the issue on July 21, after which newly sent emails delivered successfully, with previously delayed emails expected to resolve through retry.
We're currently investigating reports of an increase in Delivery Delayed events to Microsoft-hosted email addresses.
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Latest Updates ( sorted recent to last )
MONITORING
3 days ago - at 07/21/2026 04:39PM
We've received word from Microsoft that they've addressed the cause of the bounces. While it may still be possible to see emails in the Delivery Delayed status while we wait on retry, newly sent emails are now Delivered.
INVESTIGATING
3 days ago - at 07/21/2026 01:16PM
We're continuing to investigate the causes of Deliverability Delayed events with Microsoft and working with them directly. Thank you for your patience as we investigate this.
INVESTIGATING
4 days ago - at 07/20/2026 05:47PM
We're currently investigating reports of an increase in Delivery Delayed events to Microsoft-hosted email addresses.
Latest Resend outages
Domain-related webhooks delayed - 8 days ago
Increased latency in CSV imports and automation runs - 12 days ago
Increased latency across API endpoints and email sending - 14 days ago
Email sending delay - 21 days ago
Delayed webhooks - about 1 month ago
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