I had the same issue. Found the solution through the plugin author’s website:
Remove the prefix “PL” at the beginning of your playlist ID.
Example:
Change: httpvp://www.youtube.com/playlist?list=PL5BF57CC7C199AA2D
TO
httpvp://www.youtube.com/playlist?list=5BF57CC7C199AA2D
Hope this works for you too!
