When Unified Agent (UA) is installed on MAC OS, users are unable to connect to Apple resources after enabling SSL interception.
Cannot Connect to App Store
Apple Inc. products and services (including apps like iTunes, iCloud, App Store, etc.) uses certificate pinning. Basically, they only work if the client is connecting to them along with the specific Apple Inc. SSL public key, and if you are using Web Security Service (WSS) with SSL interception enabled, this can cause some issues with the access to those services.
Web Security Service
To solve this issue, bypass SSL Interception for the following destination URLs:
Instructions how to add domains to SSL interception list can be found here.