Customers running on ProxySG300/600 running pre 6.6.5.8 will have the below error when downloading source from Application Classification > General > Download > Download Now.

% Invalid response "426" from Web App Service

Download URL : https://subscription.es.bluecoat.com/classification/database

There is a limitation that SG300/600’s running earlier than 6.6.5.8 is incompatible with the full CASB dataset thus a permanent restriction for devices prior to this version. 

Upgrade the ProxySG 300/600 to 6.6.5.8 and later to be able to download the dataset.

Example:

ProxySG 300 prior to 6.6.5.8 (6.6.3.2)

ProxySG 300 on 6.6.5.8 or later