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Delayed Email Delivery (UK)

Resolved incidentMinor

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  1. Monitoring

    We've received reports of some customers having mail flow issues intermittently. We have identified and implemented a fix, however the fix may take 1-4 hours to propagate.

  2. Resolved

    This incident has been resolved.

  3. Resolved

    On Wednesday, January 21, 2026, from approximately 14:59 to Thursday, January 22, 2026, at approximately 10:11 (UTC), some customers experienced delays with outbound email delivery for UK instances of Prevent, Defend, and Protect.

    This incident was caused by an external email reputation service provider that temporarily restricted one of our outbound email IP addresses. Some messages routed through this restricted address experienced temporary delays while we attempted delivery using other sending addresses. To resolve this issue, our team reached out to the service provider to have the IP address taken off their blocklist. Once the restriction was lifted at 17:33 (UTC), our systems automatically retried the remaining queued messages, and outbound email delivery returned to normal performance by January 22, 2026, at 10:11 (UTC).

    To prevent this type of issue in the future, we are investigating additional mitigations for external reputation factors. We are also enhancing our existing monitoring to identify and respond to outbound email reputation changes more quickly.

    No data loss occurred as a result of this issue.