Why do I get errors message when adding a Netblock

In the Enforce UI the configuration section for enabling Netblocks is intended for users to add external and routable IP addresses or ranges of addresses.

If a user adds a non-routable (non-public) Netblock the UI will present errors like you see below:

For further reading about configuring Netblocks see the following articles:

Enforce Self-Onboarding Guide

Configuration of Internal Sources