You cannot download it from YouTube directly. Your only hope is that a third-party has re-uploaded it elsewhere (Vimeo, Dailymotion, or a peer-to-peer network).
While downloading blocked YouTube videos may seem appealing, it's essential to consider the copyright implications: how to download blocked youtube videos copyright
Avoid any site that asks you to download an .exe file or "Allow Notifications" to continue. Legitimate web tools will process the file in the browser and offer a direct .mp4 or .mp3 download. You cannot download it from YouTube directly