Error type: "Forbidden". Error message: "Requests from referer https://www.googleapis.com/youtube/v3/search?part=snippet&channelId=&maxResults=6&order=date&type=video&key=AIzaSyDngdTFVV3B2wxAYyuiHJ0T1ee1b0Vxr4I are blocked." Domain: "global". Reason: "forbidden".

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

Check in YouTube if the id UCofbXrEbCwCwwFtCzmqnIUg belongs to a channelid. Check the FAQ of the plugin or send error messages to support.