as a user, I am trying to access a specific website but the proxy returns the error "Your request could not be processed. Access to: "adomain.com" is not allowed through this proxy"
Web Security Service
The domain's A record contains an RFC1918 address is an IP address that is assigned to an internal host. These IP addresses are used in private networks, which are not available, or reachable, from the Internet, therefore, the proxy returns to the user accordingly
The website administrator needs to fix their domains' DNS A record under the authoritative name servers and remove any internal IPs which are non-routable IPs on the internet.
Online DNS Tools can be used to look into the domains' DNS configuration and see where the error lies: