Tipo de error: "Forbidden". Mensaje de error: "Method doesn't allow unregistered callers (callers without established identity). Please use API Key or other form of API consumer identity to call this API." Dominio: "global". Razón: "forbidden".

Did you added your own Google API key? Look at the help.

Comprueba en YouTube si el id PLBDwCGgsWKzLQchIDg6FsmlnCi83p9iDY corresponde a un playlist. Revise el FAQ del plugin or envíe los mensajes de error a support.