You can simplify the entry of the ICG server address for your users with a simple DNS tweak.
Add a TXT record for the host
igel-cloud-gateway with the contents
https://[ICG IP address]:8443/usg/endpoint
When users enter their email address
email@example.com as the server address in the ICG Agent Setup, the setup will look up this record on the
example.com nameserver and find the gateway address to connect to.