Sine incident
Microsoft 365 users seeing delayed email delivery from Sine
Resolved after 23 hours 25 minutes, affecting Sendgrid Email Gateway, on January 22, 2026.
We are continuing to investigate this issue.
Affected components
Update timeline
- investigating Jan 22, 2026, 10:16 PM UTC
Microsoft is currently experiencing issues affecting Microsoft 365 services, including problems with email delivery to and from Microsoft 365 accounts (Exchange Online). Recent reports indicate a service degradation or outage impacting inbound and outbound email functionality. Users have encountered errors such as "451 4.3.2 Temporary server error" when attempting to send or receive emails, along with intermittent failures in email delivery. Please see https://status.cloud.microsoft/m365/ for more information We will continue to monitor the issue and Sine emails will retry sending at regular intervals
- investigating Jan 23, 2026, 09:41 PM UTC
We are continuing to investigate this issue.
- resolved Jan 23, 2026, 09:41 PM UTC
https://status.cloud.microsoft/m365/ now lists the incident as resolved
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