Error type: "Forbidden". Error message: "Project 644299066901 has been scheduled for deletion and cannot be used for API calls. Visit https://console.developers.google.com/iam-admin/projects?pendingDeletion=true to undelete the project." Domain: "usageLimits". Reason: "accessNotConfigured".
Did you added your own Google API key? Look at the help.
Check in YouTube if the id UC8McZtoR7E8JHbuKgR2Y6Fw belongs to a channelid. Check the FAQ of the plugin or send error messages to support.