Can no longer download Youtube videos Rated 3 out of 5 stars

The add on has been working amazing until now, I can't download anything from Youtube. I starts the download and finishes itself with 0 bytes. Not sure if it's only me, please help.

It works fine on my laptop PC, but it no longer is working on my Mac. The only option I have now is a red play arrow. TIA

This review is for a previous version of the add-on (