Error type: "Bad Request". Error message: "API key not valid. Please pass a valid API key." Domain: "global". Reason: "badRequest".
Did you added your own Google API key? Look at the
help.
Check in YouTube if the id
UC9b0Y3ltIWsRJ2qSh74xUMw belongs to a playlist. Check the
FAQ of the plugin or send error messages to
support.