> Would it be possible for you to share more information about YouTube's download limits and practices with dealing with abuse?
We can't control and we don't know how and why youtube (or any other video hosting) blocks requests. But practice shows that if you're using tools that downloads video from youtube too often (dozens of times per day) youtube just blocks you. There are some tricks you can try:
1) Use VPN while download videos. It will change your IP and you will be able to download videos.
2) Try to launch this command from Terminal. I added "--force-ipv4" parameter, it may help. Copy and paste here output of this command.
Code:
/Applications/Parallels\ Toolbox.app/Contents/Applications/Download\ Video.app/Contents/Resources/dl --force-ipv4 https://youtu.be/zA8pVC_tPt8