When installing Smart Licensing, you are prompted to indicate which port you want the client service to listen on: the default port or a custom port.
If you choose to specify a custom port, we recommend that you select a port between 1025 and 65535. Ports 1-1024 are reserved for services that run as administrator, and specifying one of these ports will cause the installation to fail.
If you must use a port 1-1024, you must add a URL ACL rule, such as:
netsh http add urlacl url=http://localhost:123/Client
user=Everyone
where the user parameter includes whichever user the service will be running as or "everyone".