This article describes resolution or workaround to address a drop code Packet dropped - DNS sinkhole dropped the pkt when
This release includes significant user interface changes and many new features that are different from the SonicOS 6.5 and earlier firmware. The below resolution is for customers using SonicOS 7.X firmware.

This release includes significant user interface changes and many new features that are different from the SonicOS 6.2 and earlier firmware. The below resolution is for customers using SonicOS 6.5 firmware.
Navigate to Manage | System Setup | Network | DNS security | add the domain under White List 