Error type: "Forbidden". Error message: "Requests from referer are blocked." Domain: "global". Reason: "forbidden".
Did you added your own Google API key? Look at the help.
Check in YouTube if the id PL2aXRrgusxr9Hjq5zDGqnsKiFuXMsVfnQ belongs to a playlist. Check the FAQ of the plugin or send error messages to support.