Sine incident

Microsoft 365 users seeing delayed email delivery from Sine

Notice Resolved View vendor source →

Sine experienced a notice incident on January 22, 2026 affecting Sendgrid Email Gateway, lasting 23h 25m. The incident has been resolved; the full update timeline is below.

Started
Jan 22, 2026, 10:16 PM UTC
Resolved
Jan 23, 2026, 09:41 PM UTC
Duration
23h 25m
Detected by Pingoru
Jan 22, 2026, 10:16 PM UTC

Affected components

Sendgrid Email Gateway

Update timeline

  1. 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

  2. investigating Jan 23, 2026, 09:41 PM UTC

    We are continuing to investigate this issue.

  3. resolved Jan 23, 2026, 09:41 PM UTC

    https://status.cloud.microsoft/m365/ now lists the incident as resolved