Cisco — Umbrella Unblock

However, no security filter is perfect. Occasionally, legitimate business websites get caught in the crossfire—a phenomenon known as a "False Positive." When this happens, users are greeted with a "Block Page," and productivity grinds to a halt.

While unblocking access to specific websites or resources may be necessary, it's essential to consider the potential security implications: cisco umbrella unblock

This means:

Cisco Umbrella works at the (and can also proxy traffic). When you try to visit a blocked site, Umbrella returns a different IP address — usually a block page — instead of the real site’s IP. However, no security filter is perfect