May 31, 1:17pm EDT

Beginning at 10:17 AM PT on May 31st, our engineering team began investigating a problem related to mail send delays for a subset of our users. The period of time for delayed mail send was between 9:50 AM PT and 11:50 AM PT, at which point mail successfully and completely dequeued from the system. This delay affected mail sent via SMTP, web API and Marketing Campaigns and affected approximately 20% of customer accounts. For any affected messages, the average queue time was approximately 5 minutes for the period. This issue has been resolved and mail sending systems are now operating normally.