Have you tried using the "Youtube" application filter rather than a URL object (which I assume you are using now, is that correct?).
Also, as this is posted in the API section are you attempting to leverage the API to make the rule? You might reach a larger / more targeted audience posting the question to the broader Firepower forum.
FP URL filtering capability can classify the URLs based on:
Reputation (risk level)
This varies from High Risk (level 1) to Well Known (level 5)
Category + Reputation
If you select a reputation level to allow,...
Cisco Press has published a step-by-step visual guide to configuring and troubleshooting of the Cisco Firepower Threat Defense (FTD). Each consistently organized chapter on this book contains definitions of keywords, operational flowcharts, architectural ...
Wednesday January 17, 2018
This document outlines compatibility details and product update information of AMP for Endpoints regarding the Microsoft Security Updates and Knowledge Base articles (KB4072699, KB4056892) released on January 3, 2018 to a...