By Juha Saarinen on Apr 6, 2021 6:59AM Recovery time from overloading exceeded service goals. Microsoft has published a root cause analysis of an outage of its Azure Domain Name System that struck the cloud platform over Easter, causing intermittent failures for customers accessing and managing their Microsoft services globally. The problems started at around 8.30 am on April 2, when the Azure DNS servers received an anomalous surge in queries for an unspecified set of domains hosted on Microsoft's cloud. Microsoft said it was ready for such surges, with layers of caches and traffic shaping to mitigate the effect, but a bug in its DNS service made the overloading worse.