Unable to login iTunes from desktop application while under a protected network
"There was an error connecting to the apple ID server"
Create an SSL Interception Exemption Destination for the "gsa.apple.com" URL. This is the resource that apple uses to verify iTunes certificate.
Service > Network > SSL Interception > SSL Interception Exemptions > Destinations > Add > New > IP/Subnet > add "gsa.apple.com"