Tipo de error: "Forbidden". Mensaje de error: "Access Not Configured. YouTube Data API has not been used in project 551567320461 before or it is disabled. Enable it by visiting https://console.developers.google.com/apis/api/youtube.googleapis.com/overview?project=551567320461 then retry. If you enabled this API recently, wait a few minutes for the action to propagate to our systems and retry." Dominio: "usageLimits". Razón: "accessNotConfigured".

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

Comprueba en YouTube si el id MercadoNegroTV1 corresponde a un username. Revise el FAQ del plugin or envíe los mensajes de error a support.