Klaviyo change history: Issues with Campaign Sending and Scheduling

Klaviyo reported a major campaign scheduling and sending incident starting 2026-01-12 11:12 UTC, lasting 1 h 10 min and resolved at 2026-01-12 12:23 UTC. New campaigns and scheduled RAST campaigns could not send; previously scheduled non-RAST campaigns continued processing. A fix restored service and all delayed campaigns were replayed; no data loss was expected.